ICN2 Publications


  • 2D Phononic Crystals: Progress and Prospects in Hypersound and Thermal Transport Engineering

    Sledzinska M., Graczykowski B., Maire J., Chavez-Angel E., Sotomayor-Torres C.M., Alzina F. Advanced Functional Materials; 30 (8, 1904434) 2020. 10.1002/adfm.201904434. IF: 15.621

    Phononic and Photonic Nanostructures

    The central concept in phononics is the tuning of the phonon dispersion relation, or phonon engineering, which provides a means of controlling related properties such as group velocity or phonon interactions and, therefore, phonon propagation, in a wide range of frequencies depending on the geometries and sizes of the materials. Phononics exploits the present state of the art in nanofabrication to tailor dispersion relations in the range of GHz for the control of elastic waves/phonons propagation with applications toward new information technology concepts with phonons as state variable. Moreover, phonons provide an adaptable approach for supporting a coherent coupling between different state variables, and the development of nanoscale optomechanical systems during the last decade attests this prospect. The most extended approach to manipulate the phonon dispersion relation is introducing an artificial periodic modulation of the elastic properties, which is referred to as phononic crystal (PnC). Herein, the focus is on the recent experimental achievements in the fabrication and application of 2D PnCs enabling the modification of the dispersion relation of surface and membrane modes, and presenting phononic bandgaps, waveguiding, and confinement in the hypersonic regime. Furthermore, these artificial materials offer the potential of modifying and controlling the heat flow to enable new schemes in thermal management. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • A compact SPR biosensor device for the rapid and efficient monitoring of gluten-free diet directly in human urine

    Peláez E.C., Estevez M.-C., Domínguez R., Sousa C., Cebolla A., Lechuga L.M. Analytical and Bioanalytical Chemistry; 2020. 10.1007/s00216-020-02616-6. IF: 3.286

    NanoBiosensors and Bioanalytical Applications

    Celiac disease (CD) is a chronic autoimmune disorder induced in genetically susceptible individuals by the ingestion of gluten from wheat, rye, barley, or certain varieties of oats. A careful diet follow-up is necessary to avoid health complications associated with long-term gluten intake by the celiac patients. Small peptides (GIP, gluten immunogenic peptides) derived from gluten digestion, which are excreted in the urine and feces, have emerged as promising biomarkers to monitor gluten intake. We have implemented a simple and sensitive label-free point-of-care (POC) device based on surface plasmon resonance for the direct detection of these biomarkers in urine. The assay employs specific monoclonal antibodies and has been optimized for the detection of the 33-mer α2-gliadin, known as the main immunogenic peptide of wheat gluten, and for the detection of GIP. Direct detection in undiluted urine has been accomplished by using biosensing chips containing a robust and stable biorecognition layer, obtained after carefully optimizing the biofunctionalization protocol. Excellent limits of detection have been reached (1.6–4.0 ng mL−1 using mAb G12 and A1, respectively), which ensures the detection of gluten peptides even when the gluten intake is around the maximum tolerable amount in the digestive tract (< 50 mg) for celiac individuals. No sample pretreatment, extraction, or dilution is required, and the analysis takes less than 15 min. The assays have excellent reproducibility‚ as demonstrated by measuring spiked urine samples containing the same target concentration using different biofunctionalized chips prepared and stored at different periods of time (i.e., CV% of 3.58% and 11.30%, for G12- and A1-based assays, respectively). The assay has been validated with real samples. These features pave the way towards an end-user easy-to-handle biosensor device for the rapid monitoring of gluten-free diet (GFD) and follow-up of the health status in celiac patients. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

  • A copper(II) zig-zag metal–organic coordination polymer: synthesis, crystal structure, topology study, hirshfeld surface analysis and survey different conditions on morphology of a novel nano structure [Cu(L)(SCN)(H2O)2]n.2H2O

    Souri B., Hayati P., Rezvani A.R., Mendoza-Meroño R., Janczak J. Inorganic and Nano-Metal Chemistry; 50 (2): 80 - 93. 2020. 10.1080/24701556.2019.1662040. IF: 0.685

    Nanostructured Functional Materials

    One copper(II) coordination polymer compound [Cu(L)(SCN)(H2O)2]n.2H2O (1) where L stand for 2-pyridinecarboxylic acid, was synthesized following two different experimental methods, branch tube and sonochemical irradiation nano methods. Independently of the methodology used, the same crystalline phase is obtained for each compound. Single crystal X-ray analyses on compound 1 showed that Cu2+ ions are 6-coordinated. Additionally, H-bonds incorporate the zig-zag chains in 1 into 2D (along (1,1,0) direction) frameworks. Topological analysis shows that the compound 1 is 2C1 net. Hirshfeld surface analysis of compound 1 was studied. Also, theoretical and experimental morphology were studied. The thermal stability of compound 1 was studied by thermal gravimetric. Finally, the role of reaction time and temperature on growth and final morphology of the structures obtained by sonochemical irradiation are investigated. The results indicated that particle size was reduced with increasing sonication power, temperature, sonication time and decreasing concentration of reactant. © 2019, © 2019 Taylor & Francis Group, LLC.

  • A First Evaluation of Thick Oxide 3C-SiC MOS Capacitors Reliability

    Li F., Mawby P., Song Q., Perez-Tomas A., Shah V., Sharma Y., Hamilton D., Fisher C., Gammon P., Jennings M. IEEE Transactions on Electron Devices; 67 (1, 8935512): 237 - 242. 2020. 10.1109/TED.2019.2954911. IF: 2.704

    Advanced Electronic Materials and Devices

    Despite the recent advances in 3C-SiC technology, there is a lack of statistical analysis on the reliability of SiO2 layers on 3C-SiC, which is crucial in power MOS device developments. This article presents a comprehensive study of the medium-and long-term time-dependent dielectric breakdowns (TDDBs) of 65-nm-thick SiO2 layers thermally grown on a state-of-the-art 3C-SiC/Si wafer. Fowler-Nordheim (F-N) tunneling is observed above 7 MV/cm and an effective barrier height of 3.7 eV is obtained, which is the highest known for native SiO2 layers grown on the semiconductor substrate. The observed dependence of the oxide reliability on the gate active area suggests that the oxide quality has not reached the intrinsic level. Three failure mechanisms were identified and confirmed by both medium-and long-term results. Although two of them are likely due to extrinsic defects from material quality and fabrication steps, the one dominating the high field (>8.5 MV/cm) should be attributed to the electron impact ionization within SiO2. At room temperature, the field acceleration factor is found to be ≈0.906 dec/(MV/cm) for high fields, and the projected lifetime exceeds 10 years at 4.5 MV/cm. © 1963-2012 IEEE.

  • A lab-on-a-chip system with an embedded porous membrane-based impedance biosensor array for nanoparticle risk assessment on placental Bewo trophoblast cells

    Schuller P., Rothbauer M., Kratz S.R.A., Höll G., Taus P., Schinnerl M., Genser J., Bastus N., Moriones O.H., Puntes V., Huppertz B., Siwetz M., Wanzenböck H., Ertl P. Sensors and Actuators, B: Chemical; 312 (127946) 2020. 10.1016/j.snb.2020.127946. IF: 6.393

    Inorganic Nanoparticles

    The human placenta is a unique organ serving as the lung, gut, liver, and kidney of the fetus, mediating the exchange of different endogenous as well as exogenous substances and gases between the mother and fetus during pregnancy. Additionally, the placental barrier protects the fetus from a range of environmental toxins, bacterial and viral infections, since any contaminant bridging the placenta may have unforeseeable effects on embryonal and fetal development. A more recent concern in placenta research, however, involves the ability of engineered nanoparticles to cross the placental barrier and/or affect its barrier function. To advance nanoparticle risk assessment at the human placental barrier, we have developed as proof-of-principle a highly integrated placenta-on-a-chip system containing embedded membrane-bound impedance microsensor arrays capable of non-invasively monitoring placental barrier integrity. Barrier integrity is continuously and label-free evaluated using porous membrane-based interdigitated electrode structures located on top of a porous PET membrane supporting a barrier of trophoblast-derived BeWo cell barrier in the absence and presence of standardized silicon dioxide (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) nanomaterials. © 2020 Elsevier B.V.

  • A SnS2 Molecular Precursor for Conformal Nanostructured Coatings

    Zuo Y., Li J., Yu X., Du R., Zhang T., Wang X., Arbiol J., Llorca J., Cabot A. Chemistry of Materials; 32 (5): 2097 - 2106. 2020. 10.1021/acs.chemmater.9b05241. IF: 10.159

    Advanced Electron Nanoscopy

    We present a simple, versatile, and scalable procedure to produce SnS2 nanostructured layers based on an amine/thiol-based molecular ink. The ratios amine/thiol and Sn/S, and the reaction conditions, are systematically investigated to produce phase-pure SnS2 planar and conformal layers with a tremella-like SnS2 morphology. Such nanostructured layers are characterized by excellent photocurrent densities. The same strategy can be used to produce SnS2-graphene composites by simply introducing graphene oxide (GO) into the initial solution. Conveniently, the solvent mixture is able to simultaneously dissolve the Sn and Se powders and reduce the GO. Furthermore, SnS2-xSex ternary coatings and phase-pure SnSe2 can be easily produced by simply incorporating proper amounts of Se into the initial ink formulation. Finally, the potential of this precursor ink to produce gram-scale amounts of unsupported SnS2 is investigated. Copyright © 2020 American Chemical Society.

  • A unique ZnFe2O4/graphene nanoplatelets nanocomposite for electrochemical energy storage and efficient visible light driven catalysis for the degradation of organic noxious in wastewater

    Israr M., Iqbal J., Arshad A., Aisida S.O., Ahmad I. Journal of Physics and Chemistry of Solids; 140 (109333) 2020. 10.1016/j.jpcs.2020.109333. IF: 2.752

    Novel Energy-Oriented Materials

    A series of ZnFe2O4/graphene nanoplatelets ((ZF)1-x(GNPs)x) nanocomposites have been synthesized and characterized. By optimizing the weight ratio of graphene nanoplatelets (GNPs), the synthesized nanocomposites have been identified as an excellent material for electrochemical capacitors with outstanding electrochemical capacitance (314 Fg−1at 0.5 Ag−1), high rate performance, and long-standing cyclic stability (77.6% retention). The enhanced electrochemical performance might be adduced to the improved electrode/electrolyte charge transfer interface and conducting nature of GNPs. Besides, (ZF)1-x(GNPs)x nanocomposites exhibit outstanding visible light driven photocatalytic efficiency for the removal of methylene blue (MB) dye in water i.e., 97.46% of the MB is degraded in 70 min, which can be primarily ascribed to the enhanced photo Fenton reaction, effective electron-hole (e−/h+) separation and strong interfacial coupling between ZnFe2O4 nanoparticles (ZF NPs) and GNPs. Our results offer new insights into multifunctional nanocomposites for the electrochemical energy storage and treatment of polluted wastewater. © 2020

  • ABINIT: Overview and focus on selected capabilities

    Romero A.H., Allan D.C., Amadon B., Antonius G., Applencourt T., Baguet L., Bieder J., Bottin F., Bouchet J., Bousquet E., Bruneval F., Brunin G., Caliste D., Côté M., Denier J., Dreyer C., Ghosez P., Giantomassi M., Gillet Y., Gingras O., Hamann D.R., Hautier G., Jollet F., Jomard G., Martin A., Miranda H.P.C., Naccarato F., Petretto G., Pike N.A., Planes V., Prokhorenko S., Rangel T., Ricci F., Rignanese G.-M., Royo M., Stengel M., Torrent M., Van Setten M.J., Van Troeye B., Verstraete M.J., Wiktor J., Zwanziger J.W., Gonze X. Journal of Chemical Physics; 152 (12, 124102) 2020. 10.1063/1.5144261. IF: 2.997

    Theory and Simulation

    abinit is probably the first electronic-structure package to have been released under an open-source license about 20 years ago. It implements density functional theory, density-functional perturbation theory (DFPT), many-body perturbation theory (GW approximation and Bethe-Salpeter equation), and more specific or advanced formalisms, such as dynamical mean-field theory (DMFT) and the "temperature-dependent effective potential" approach for anharmonic effects. Relying on planewaves for the representation of wavefunctions, density, and other space-dependent quantities, with pseudopotentials or projector-augmented waves (PAWs), it is well suited for the study of periodic materials, although nanostructures and molecules can be treated with the supercell technique. The present article starts with a brief description of the project, a summary of the theories upon which abinit relies, and a list of the associated capabilities. It then focuses on selected capabilities that might not be present in the majority of electronic structure packages either among planewave codes or, in general, treatment of strongly correlated materials using DMFT; materials under finite electric fields; properties at nuclei (electric field gradient, Mössbauer shifts, and orbital magnetization); positron annihilation; Raman intensities and electro-optic effect; and DFPT calculations of response to strain perturbation (elastic constants and piezoelectricity), spatial dispersion (flexoelectricity), electronic mobility, temperature dependence of the gap, and spin-magnetic-field perturbation. The abinit DFPT implementation is very general, including systems with van der Waals interaction or with noncollinear magnetism. Community projects are also described: generation of pseudopotential and PAW datasets, high-throughput calculations (databases of phonon band structure, second-harmonic generation, and GW computations of bandgaps), and the library libpaw. abinit has strong links with many other software projects that are briefly mentioned. © 2020 Author(s).

  • Addressing Nanomaterial Immunosafety by Evaluating Innate Immunity across Living Species

    Boraschi D., Alijagic A., Auguste M., Barbero F., Ferrari E., Hernadi S., Mayall C., Michelini S., Navarro Pacheco N.I., Prinelli A., Swart E., Swartzwelter B.J., Bastús N.G., Canesi L., Drobne D., Duschl A., Ewart M.-A., Horejs-Hoeck J., Italiani P., Kemmerling B., Kille P., Prochazkova P., Puntes V.F., Spurgeon D.J., Svendsen C., Wilde C.J., Pinsino A. Small; 16 (21, 2000598) 2020. 10.1002/smll.202000598. IF: 10.856

    Inorganic Nanoparticles

    The interaction of a living organism with external foreign agents is a central issue for its survival and adaptation to the environment. Nanosafety should be considered within this perspective, and it should be examined that how different organisms interact with engineered nanomaterials (NM) by either mounting a defensive response or by physiologically adapting to them. Herein, the interaction of NM with one of the major biological systems deputed to recognition of and response to foreign challenges, i.e., the immune system, is specifically addressed. The main focus is innate immunity, the only type of immunity in plants, invertebrates, and lower vertebrates, and that coexists with adaptive immunity in higher vertebrates. Because of their presence in the majority of eukaryotic living organisms, innate immune responses can be viewed in a comparative context. In the majority of cases, the interaction of NM with living organisms results in innate immune reactions that eliminate the possible danger with mechanisms that do not lead to damage. While in some cases such interaction may lead to pathological consequences, in some other cases beneficial effects can be identified. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • An Interlaboratory Study on the Stability of All-Printable Hole Transport Material–Free Perovskite Solar Cells

    De Rossi F., Barbé J., Tanenbaum D.M., Cinà L., Castriotta L.A., Stoichkov V., Wei Z., Tsoi W.C., Kettle J., Sadula A., Chircop J., Azzopardi B., Xie H., Di Carlo A., Lira-Cantú M., Katz E.A., Watson T.M., Brunetti F. Energy Technology; 2020. 10.1002/ente.202000134. IF: 3.163

    Nanostructured Materials for Photovoltaic Energy

    Comparisons between different laboratories on long-term stability analyses of perovskite solar cells (PSCs) is still lacking in the literature. This work presents the results of an interlaboratory study conducted between five laboratories from four countries. Carbon-based PSCs are prepared by screen printing, encapsulated, and sent to different laboratories across Europe to assess their stability by the application of three ISOS aging protocols: (a) in the dark (ISOS-D), (b) under simulated sunlight (ISOS-L), and (c) outdoors (ISOS-O). Over 1000 h stability is reported for devices in the dark, both at room temperature and at 65 °C. Under continuous illumination at open circuit, cells survive only for few hours, although they recover after being stored in the dark. Better stability is observed for cells biased at maximum power point under illumination. Finally, devices operate in outdoors for 30 days, with minor degradation, in two different locations (Barcelona, Spain and Paola, Malta). The findings demonstrate that open-circuit conditions are too severe for stability assessment and that the diurnal variation of the photovoltaic parameters reveals performance to be strongly limited by the fill factor, in the central hours of the day, due to the high series resistance of the carbon electrode. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • An overview of microencapsulation in the food industry: opportunities, challenges, and innovations

    Arenas-Jal M., Suñé-Negre J.M., García-Montoya E. European Food Research and Technology; 2020. 10.1007/s00217-020-03496-x. IF: 2.056

    Supramolecular NanoChemistry and Materials

    While consumer trends are leading to a surge of functional foods, the addition of bioactive compounds to food matrixes presents a series of challenges such as lack of stability or unpleasant organoleptic characteristics. Microencapsulation is not only a useful tool to overcome them, but it also allows the development of products with improved features that allow the differentiation from competitors and personalization of products. Despite consumers increasingly recognize the benefits of technological solutions, the healthy living and clean labeling trends are also posing challenges for microencapsulation. Thus, considering the limited range of suitable encapsulant materials allowed for food, material selection is becoming the main challenge that formulators face. In this review, opportunities, challenges, and innovations of microencapsulation in the food industry have been discussed. In addition, an overview on microencapsulation, reasons for microencapsulation, its techniques, and examples of applications in the food industry have also been provided. Graphic abstract: [Figure not available: see fulltext.]. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

  • Band Depopulation of Graphene Nanoribbons Induced by Chemical Gating with Amino Groups

    Li J., Brandimarte P., Vilas-Varela M., Merino-Díez N., Moreno C., Mugarza A., Mollejo J.S., Sánchez-Portal D., Garcia De Oteyza D., Corso M., Garcia-Lekue A., Peña D., Pascual J.I. ACS Nano; 14 (2): 1895 - 1901. 2020. 10.1021/acsnano.9b08162. IF: 13.903

    Atomic Manipulation and Spectroscopy

    The electronic properties of graphene nanoribbons (GNRs) can be precisely tuned by chemical doping. Here we demonstrate that amino (NH2) functional groups attached at the edges of chiral GNRs (chGNRs) can efficiently gate the chGNRs and lead to the valence band (VB) depopulation on a metallic surface. The NH2-doped chGNRs are grown by on-surface synthesis on Au(111) using functionalized bianthracene precursors. Scanning tunneling spectroscopy resolves that the NH2 groups significantly upshift the bands of chGNRs, causing the Fermi level crossing of the VB onset of chGNRs. Through density functional theory simulations we confirm that the hole-doping behavior is due to an upward shift of the bands induced by the edge NH2 groups. © 2020 American Chemical Society.

  • Banning carbon nanotubes would be scientifically unjustified and damaging to innovation

    Heller D.A., Jena P.V., Pasquali M., Kostarelos K., Delogu L.G., Meidl R.E., Rotkin S.V., Scheinberg D.A., Schwartz R.E., Terrones M., Wang Y.H., Bianco A., Boghossian A.A., Cambré S., Cognet L., Corrie S.R., Demokritou P., Giordani S., Hertel T., Ignatova T., Islam M.F., Iverson N.M., Jagota A., Janas D., Kono J., Kruss S., Landry M.P., Li Y., Martel R., Maruyama S., Naumov A.V., Prato M., Quinn S.J., Roxbury D., Strano M.S., Tour J.M., Weisman R.B., Wenseleers W., Yudasaka M. Nature Nanotechnology; 15 (3): 164 - 166. 2020. 10.1038/s41565-020-0656-y. IF: 33.407


    [No abstract available]

  • Biomimetic Synthesis of Sub-20 nm Covalent Organic Frameworks in Water

    Franco C., Rodríguez-San-Miguel D., Sorrenti A., Sevim S., Pons R., Platero-Prats A.E., Pavlovic M., Szilágyi I., Ruiz Gonzalez M.L., González-Calbet J.M., Bochicchio D., Pesce L., Pavan G.M., Imaz I., Cano-Sarabia M., Maspoch D., Pané S., De Mello A.J., Zamora F., Puigmartí-Luis J. Journal of the American Chemical Society; 142 (7): 3540 - 3547. 2020. 10.1021/jacs.9b12389. IF: 14.695

    Supramolecular NanoChemistry and Materials

    Covalent organic frameworks (COFs) are commonly synthesized under harsh conditions yielding unprocessable powders. Control in their crystallization process and growth has been limited to studies conducted in hazardous organic solvents. Herein, we report a one-pot synthetic method that yields stable aqueous colloidal solutions of sub-20 nm crystalline imine-based COF particles at room temperature and ambient pressure. Additionally, through the combination of experimental and computational studies, we investigated the mechanisms and forces underlying the formation of such imine-based COF colloids in water. Further, we show that our method can be used to process the colloidal solution into 2D and 3D COF shapes as well as to generate a COF ink that can be directly printed onto surfaces. These findings should open new vistas in COF chemistry, enabling new application areas. Copyright © 2020 American Chemical Society.

  • Broadband Dynamic Polarization Conversion in Optomechanical Metasurfaces

    Zanotto S., Colombano M., Navarro-Urrios D., Biasiol G., Sotomayor-Torres C.M., Tredicucci A., Pitanti A. Frontiers in Physics; 7 (231) 2020. 10.3389/fphy.2019.00231. IF: 1.895

    Phononic and Photonic Nanostructures

    Artificial photonic materials, nanofabricated through wavelength-scale engineering, have shown astounding and promising results in harnessing, tuning, and shaping photonic beams. Metamaterials have proven to be often outperforming the natural materials they take inspiration from. In particular, metallic chiral metasurfaces have demonstrated large circular and linear dichroism of light which can be used, for example, for probing different enantiomers of biological molecules. Moreover, the precise control, through designs on demand, of the output polarization state of light impinging on a metasurface, makes this kind of structures particularly relevant for polarization-based telecommunication protocols. The reduced scale of the metasurfaces makes them also appealing for integration with nanomechanical elements, adding new dynamical features to their otherwise static or quasi-static polarization properties. To this end we designed, fabricated and characterized an all-dielectric metasurface on a suspended nanomembrane. Actuating the membrane mechanical motion, we show how the metasurface reflectance response can be modified, according to the spectral region of operation, with a corresponding intensity modulation or polarization conversion. The broad mechanical resonance at atmospheric pressure, centered at about 400 kHz, makes the metasurfaces structure suitable for high-frequency operation, mainly limited by the piezo-actuator controlling the mechanical displacement, which in our experiment reached modulation frequencies exceeding 1.3 MHz. © Copyright © 2020 Zanotto, Colombano, Navarro-Urrios, Biasiol, Sotomayor-Torres, Tredicucci and Pitanti.

  • Cerium Oxide Nanoparticles: Advances in Biodistribution, Toxicity, and Preclinical Exploration

    Casals E., Zeng M., Parra-Robert M., Fernández-Varo G., Morales-Ruiz M., Jiménez W., Puntes V., Casals G. Small; 16 (20, 1907322) 2020. 10.1002/smll.201907322. IF: 10.856

    Inorganic Nanoparticles

    Antioxidant nanoparticles have recently gained tremendous attention for their enormous potential in biomedicine. However, discrepant reports of either medical benefits or toxicity, and lack of reproducibility of many studies, generate uncertainties delaying their effective implementation. Herein, the case of cerium oxide is considered, a well-known catalyst in the petrochemistry industry and one of the first antioxidant nanoparticles proposed for medicine. Like other nanoparticles, it is now described as a promising therapeutic alternative, now as threatening to health. Sources of these discrepancies and how this analysis helps to overcome contradictions found for other nanoparticles are summarized and discussed. For the context of this analysis, what has been reported in the liver is reviewed, where many diseases are related to oxidative stress. Since well-dispersed nanoparticles passively accumulate in liver, it represents a major testing field for the study of new nanomedicines and their clinical translation. Even more, many contradictory works have reported in liver either cerium-oxide-associated toxicity or protection against oxidative stress and inflammation. Based on this, finally, the intention is to propose solutions to design improved nanoparticles that will work more precisely in medicine and safely in society. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Charge transfer in steam purified arc discharge single walled carbon nanotubes filled with lutetium halides

    Santidrián A., Kierkowicz M., Pach E., Darvasiová D., Ballesteros B., Tobias G., Kalbáč M. Physical Chemistry Chemical Physics; 22 (18): 10063 - 10075. 2020. 10.1039/d0cp01408g. IF: 3.567

    Electron Microscopy Unit

    In the present work, the effect of doping on electronic properties in bulk purified and filled arc-discharge single-walled carbon nanotubes samples is studied for the first time by in situ Raman spectroelectrochemical method. A major challenge to turn the potential of SWCNTs into customer applications is to reduce or eliminate their contaminants by means of purification techniques. Besides, the endohedral functionalization of SWCNTs with organic and inorganic materials (i.e. metal halides) allows the development of tailored functional hybrids. Here, we report the purification and endohedral functionalization of SWCNTs with doping affecting the SWCNTs. Steam-purified SWCNTs have been filled with selected lutetium(iii) halides, LuCl3, LuBr3, LuI3, and sealed using high-temperature treatment, yielding closed-ended SWCNTs with the filling material confined in the inner cavity. The purified SWCNTs were studied using TGA, EDX, STEM and Raman spectroscopy. The lutetium(iii) halide-filled SWCNTs (LuX3@SWCNTs) were characterized using STEM, EDX, Raman spectroscopy and in situ Raman spectroelectrochemistry. It was found that there is a charge transfer between the SWCNTs and the encapsulated LuX3 (X = Cl, Br, I). The obtained data testify to the acceptor doping effect of lutetium(iii) halides incorporated into the SWCNT channels, which is accompanied by the charge transfer from nanotube walls to the introduced substances. © 2020 the Owner Societies.

  • Chitin Nanofiber Paper toward Optical (Bio)sensing Applications

    Naghdi T., Golmohammadi H., Yousefi H., Hosseinifard M., Kostiv U., Horák D., Merkoçi A. ACS Applied Materials and Interfaces; 12 (13): 15538 - 15552. 2020. 10.1021/acsami.9b23487. IF: 8.456

    Nanobioelectronics and Biosensors

    Because of numerous inherent and unrivaled features of nanofibers made of chitin, the second most plentiful natural-based polymer (after cellulose), including affordability, abundant nature, biodegradability, biocompatibility, commercial availability, flexibility, transparency, and extraordinary mechanical and physicochemical properties, chitin nanofibers (ChNFs) are being applied as one of the most appealing bionanomaterials in a myriad of fields. Herein, we exploited the beneficial properties offered by the ChNF paper to fabricate transparent, efficient, biocompatible, flexible, and miniaturized optical sensing bioplatforms via embedding/immobilizing various plasmonic nanoparticles (silver and gold nanoparticles), photoluminescent nanoparticles (CdTe quantum dots, carbon dots, and NaYF4:Yb3+@Er3+&SiO2 upconversion nanoparticles) along with colorimetric reagents (curcumin, dithizone, etc.) in the 3D nanonetwork scaffold of the ChNF paper. Several configurations, including 2D multi-wall and 2D cuvette patterns with hydrophobic barriers/walls and hydrophilic test zones/channels, were easily printed using laser printing technology or punched as spot patterns on the dried ChNF paper-based nanocomposites to fabricate the (bio)sensing platforms. A variety of (bio)chemicals as model analytes were used to confirm the efficiency and applicability of the fabricated ChNF paper-based sensing bioplatforms. The developed (bio)sensors were also coupled with smartphone technology to take the advantages of smartphone-based monitoring/sensing devices along with the Internet of Nano Things (IoNT)/the Internet of Medical Things (IoMT) concepts for easy-to-use sensing applications. Building upon the unrivaled and inherent features of ChNF as a very promising bionanomaterial, we foresee that the ChNF paper-based sensing bioplatforms will emerge new opportunities for the development of innovative strategies to fabricate cost-effective, simple, smart, transparent, biodegradable, miniaturized, flexible, portable, and easy-to-use (bio)sensing/monitoring devices. Copyright © 2020 American Chemical Society.

  • Cobalt atoms drive the anchoring of Co-TPP molecules to the oxygen-passivated Fe(0 0 1) surface

    Calloni A., Jagadeesh M.S., Bussetti G., Fratesi G., Achilli S., Picone A., Lodesani A., Brambilla A., Goletti C., Ciccacci F., Duò L., Finazzi M., Goldoni A., Verdini A., Floreano L. Applied Surface Science; 505 (144213) 2020. 10.1016/j.apsusc.2019.144213. IF: 5.155

    Theory and Simulation

    We present a multitechnique investigation of the structural and electronic properties of the prototypical system composed by ultra-thin films of magnetic molecules [Co-tetraphenyl-porphyrins (Co-TPP)] grown on a ferromagnetic substrate [oxygen passivated Fe(0 0 1), namely the Fe(0 0 1)-p(1 × 1)O surface]. Low Energy electron diffraction (LEED) and scanning tunneling microscopy (STM), coupled with first-principles calculations, reveal the formation of a commensurate superstructure at monolayer coverage, made by a square array of flat-lying TPP molecules. UV–photoemission and inverse photoemission spectroscopies (UPS and IPES) are used to investigate their electronic structure. Similar to our previous results on the Zn–TPP growth on Fe(0 0 1)–p(1 × 1)O, the passivation of the metallic surface is able to preserve the photoemission features characteristic of quasi-free molecules, opening the route towards an exploitation of single oxide layers as protective films in organic/inorganic junctions. X-ray photoemission (XPS) and near edge X-ray adsorption fine structure spectroscopies (NEXAFS), are used to reveal the details of the Co–TPP interaction with the substrate. © 2019 Elsevier B.V.

  • Coherent Epitaxial Semiconductor-Ferromagnetic Insulator InAs/EuS Interfaces: Band Alignment and Magnetic Structure

    Liu Y., Luchini A., Martí-Sánchez S., Koch C., Schuwalow S., Khan S.A., Stankevič T., Francoual S., Mardegan J.R.L., Krieger J.A., Strocov V.N., Stahn J., Vaz C.A.F., Ramakrishnan M., Staub U., Lefmann K., Aeppli G., Arbiol J., Krogstrup P. ACS Applied Materials and Interfaces; 12 (7): 8780 - 8787. 2020. 10.1021/acsami.9b15034. IF: 8.456

    Advanced Electron Nanoscopy

    Hybrid semiconductor-ferromagnetic insulator heterostructures are interesting due to their tunable electronic transport, self-sustained stray field, and local proximitized magnetic exchange. In this work, we present lattice-matched hybrid epitaxy of semiconductor-ferromagnetic insulator InAs/EuS heterostructures and analyze the atomic-scale structure and their electronic and magnetic characteristics. The Fermi level at the InAs/EuS interface is found to be close to the InAs conduction band and in the band gap of EuS, thus preserving the semiconducting properties. Both neutron and X-ray reflectivity measurements show that the overall ferromagnetic component is mainly localized in the EuS thin film with a suppression of the Eu moment in the EuS layer nearest the InAs and magnetic moments outside the detection limits on the pure InAs side. This work presents a step toward realizing defect-free semiconductor-ferromagnetic insulator epitaxial hybrids for spin-lifted quantum and spintronic applications without external magnetic fields. Copyright © 2019 American Chemical Society.

  • Consensus statement for stability assessment and reporting for perovskite photovoltaics based on ISOS procedures

    Khenkin M.V., Katz E.A., Abate A., Bardizza G., Berry J.J., Brabec C., Brunetti F., Bulović V., Burlingame Q., Di Carlo A., Cheacharoen R., Cheng Y.-B., Colsmann A., Cros S., Domanski K., Dusza M., Fell C.J., Forrest S.R., Galagan Y., Di Girolamo D., Grätzel M., Hagfeldt A., von Hauff E., Hoppe H., Kettle J., Köbler H., Leite M.S., Liu S.F., Loo Y.-L., Luther J.M., Ma C.-Q., Madsen M., Manceau M., Matheron M., McGehee M., Meitzner R., Nazeeruddin M.K., Nogueira A.F., Odabaşı Ç., Osherov A., Park N.-G., Reese M.O., De Rossi F., Saliba M., Schubert U.S., Snaith H.J., Stranks S.D., Tress W., Troshin P.A., Turkovic V., Veenstra S., Visoly-Fisher I., Walsh A., Watson T., Xie H., Yıldırım R., Zakeeruddin S.M., Zhu K., Lira-Cantu M. Nature Energy; 5 (1): 35 - 49. 2020. 10.1038/s41560-019-0529-5. IF: 54.000

    Nanostructured Materials for Photovoltaic Energy

    Improving the long-term stability of perovskite solar cells is critical to the deployment of this technology. Despite the great emphasis laid on stability-related investigations, publications lack consistency in experimental procedures and parameters reported. It is therefore challenging to reproduce and compare results and thereby develop a deep understanding of degradation mechanisms. Here, we report a consensus between researchers in the field on procedures for testing perovskite solar cell stability, which are based on the International Summit on Organic Photovoltaic Stability (ISOS) protocols. We propose additional procedures to account for properties specific to PSCs such as ion redistribution under electric fields, reversible degradation and to distinguish ambient-induced degradation from other stress factors. These protocols are not intended as a replacement of the existing qualification standards, but rather they aim to unify the stability assessment and to understand failure modes. Finally, we identify key procedural information which we suggest reporting in publications to improve reproducibility and enable large data set analysis. © 2020, The Author(s).

  • Cooling and self-oscillation in a nanotube electromechanical resonator

    Urgell C., Yang W., De Bonis S.L., Samanta C., Esplandiu M.J., Dong Q., Jin Y., Bachtold A. Nature Physics; 16 (1): 32 - 37. 2020. 10.1038/s41567-019-0682-6. IF: 20.113

    Magnetic Nanostructures

    Nanomechanical resonators are used with great success to couple mechanical motion to other degrees of freedom, such as photons, spins and electrons1,2. The motion of a mechanical eigenmode can be efficiently cooled into the quantum regime using photons2–4, but not other degrees of freedom. Here, we demonstrate a simple yet powerful method for cooling, amplification and self-oscillation using electrons. This is achieved by applying a constant (d.c.) current of electrons through a suspended nanotube in a dilution refrigerator. We demonstrate cooling to 4.6 ± 2.0 quanta of vibrations. We also observe self-oscillation, which can lead to prominent instabilities in the electron transport through the nanotube. We attribute the origin of the observed cooling and self-oscillation to an electrothermal effect. This work shows that electrons may become a useful resource for cooling the mechanical vibrations of nanoscale systems into the quantum regime. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.

  • Detection and Quantification of HspX Antigen in Sputum Samples Using Plasmonic Biosensing: Toward a Real Point-of-Care (POC) for Tuberculosis Diagnosis

    Peláez E.C., Estevez M.C., Mongui A., Menéndez M.-C., Toro C., Herrera-Sandoval O.L., Robledo J., García M.J., Portillo P.D., Lechuga L.M. ACS infectious diseases; 6 (5): 1110 - 1120. 2020. 10.1021/acsinfecdis.9b00502. IF: 4.911

    NanoBiosensors and Bioanalytical Applications

    Advancements that occurred during the last years in the diagnosis of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis infection, have prompted increased survival rates of patients. However, limitations related to the inefficiency of an early detection still remain; some techniques and laboratory methods do not have enough specificity and most instruments are expensive and require handling by trained staff. In order to contribute to a prompt and effective diagnosis of tuberculosis, we report the development of a portable, user-friendly, and low-cost biosensor device for its early detection. By using a label-free surface plasmon resonance (SPR) biosensor, we have established a direct immunoassay for the direct detection and quantification of the heat shock protein X (HspX) of Mtb, a well-established biomarker of this pathogen, directly in pretreated sputum samples. The method relies on highly specific monoclonal antibodies that are previously immobilized on the plasmonic sensor surface. This technology allows for the direct detection of the biomarker without amplification steps, showing a limit of detection (LOD) of 0.63 ng mL-1 and a limit of quantification (LOQ) of 2.12 ng mL-1. The direct analysis in pretreated sputum shows significant differences in the HspX concentration in patients with tuberculosis (with concentration levels in the order of 116-175 ng mL-1) compared with non-tuberculosis infected patients (values below the LOQ of the assay).

  • Differential properties and effects of fluorescent carbon nanoparticles towards intestinal theranostics

    Vallan L., Hernández-Ferrer J., Grasa L., González-Domínguez J.M., Martínez M.T., Ballesteros B., Urriolabeitia E.P., Ansón-Casaos A., Benito A.M., Maser W.K. Colloids and Surfaces B: Biointerfaces; 185 (110612) 2020. 10.1016/j.colsurfb.2019.110612. IF: 3.973

    Electron Microscopy Unit

    Given the potential applications of fluorescent carbon nanoparticles in biomedicine, the relationship between their chemical structure, optical properties and biocompatibility has to be investigated in detail. In this work, different types of fluorescent carbon nanoparticles are synthesized by acid treatment, sonochemical treatment, electrochemical cleavage and polycondensation. The particle size ranges from 1 to 6 nm, depending on the synthesis method. Nanoparticles that were prepared by acid or sonochemical treatments from graphite keep a crystalline core and can be classified as graphene quantum dots. The electrochemically produced nanoparticles do not clearly show the graphene core, but it is made of heterogeneous aromatic structures with limited size. The polycondensation nanoparticles do not have C[dbnd]C double bonds. The type of functional groups on the carbon backbone and the optical properties, both absorbance and photoluminescence, strongly depend on the nanoparticle origin. The selected types of nanoparticles are compatible with human intestinal cells, while three of them also show activity against colon cancer cells. The widely different properties of the nanoparticle types need to be considered for their use as diagnosis markers and therapeutic vehicles, specifically in the digestive system. © 2019 Elsevier B.V.

  • Distortion-Free Sensing of Neural Activity Using Graphene Transistors

    Garcia-Cortadella R., Masvidal-Codina E., De la Cruz J.M., Schäfer N., Schwesig G., Jeschke C., Martinez-Aguilar J., Sanchez-Vives M.V., Villa R., Illa X., Sirota A., Guimerà A., Garrido J.A. Small; 16 (16, 1906640) 2020. 10.1002/smll.201906640. IF: 10.856

    Advanced Electronic Materials and Devices

    Graphene solution-gated field-effect transistors (g-SGFETs) are promising sensing devices to transduce electrochemical potential signals in an electrolyte bath. However, distortion mechanisms in g-SGFET, which can affect signals of large amplitude or high frequency, have not been evaluated. Here, a detailed characterization and modeling of the harmonic distortion and non-ideal frequency response in g-SGFETs is presented. This accurate description of the input–output relation of the g-SGFETs allows to define the voltage- and frequency-dependent transfer functions, which can be used to correct distortions in the transduced signals. The effect of signal distortion and its subsequent calibration are shown for different types of electrophysiological signals, spanning from large amplitude and low frequency cortical spreading depression events to low amplitude and high frequency action potentials. The thorough description of the distortion mechanisms presented in this article demonstrates that g-SGFETs can be used as distortion-free signal transducers not only for neural sensing, but also for a broader range of applications in which g-SGFET sensors are used. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Editorial note - Professor Turner's retirement

    Gu M.B., Li C., Merkoçi A., the new editorial team of Biosensors and Bioelectronics, Co-Editors in chief Biosensors and Bioelectronics; 150 (111913) 2020. 10.1016/j.bios.2019.111913. IF: 9.518

    Nanobioelectronics and Biosensors

    [No abstract available]

  • Electrophoretic origin of long-range repulsion of colloids near water/Nafion interfaces

    Esplandiu M.J., Reguera D., Fraxedas J. Soft Matter; 16 (15): 3717 - 3726. 2020. 10.1039/d0sm00170h. IF: 3.399

    Magnetic Nanostructures | Force Probe Microscopy and Surface Nanoengineering

    One of the most striking properties of Nafion is the formation of a long-range solute exclusion zone (EZ) in contact with water. The mechanism of formation of this EZ has been the subject of a controversial and long-standing debate. Previous studies by Schurr et al. and Florea et al. root the explanation of this phenomenon in the ion-exchange properties of Nafion, which generates ion diffusion and ion gradients that drive the repulsion of solutes by diffusiophoresis. Here we have evaluated separately the electrophoretic and chemiphoretic contributions to multi-ionic diffusiophoresis using differently charged colloidal tracers as solutes to identify better their contribution in the EZ formation. Our experimental results, which are also supported by numerical simulations, show that the electric field, built up due to the unequal diffusion coefficients of the exchanged ions, is the dominant parameter behind such interfacial phenomenon in the presence of alkali metal chlorides. The EZ formation depends on the interplay of the electric field with the zeta potential of the solute and can be additionally modulated by changing ion diffusion coefficients or adding salts. As a consequence, we show that not all solutes can be expelled from the Nafion interface and hence the EZ is not always formed. This study thus provides a more detailed description of the origin and dynamics of this phenomenon and opens the door to the rational use of this active interface for many potential applications. This journal is © The Royal Society of Chemistry.

  • Element- and Time-Resolved Measurements of Spin Dynamics Using X-ray Detected Ferromagnetic Resonance

    Klewe C., Li Q., Yang M., N’Diaye A.T., Burn D.M., Hesjedal T., Figueroa A.I., Hwang C., Li J., Hicken R.J., Shafer P., Arenholz E., van der Laan G., Qiu Z. Synchrotron Radiation News; 33 (2): 12 - 19. 2020. 10.1080/08940886.2020.1725796.

    Physics and Engineering of Nanodevices

    [No abstract available]

  • Engineering grain boundaries at the 2D limit for the hydrogen evolution reaction

    He Y., Tang P., Hu Z., He Q., Zhu C., Wang L., Zeng Q., Golani P., Gao G., Fu W., Huang Z., Gao C., Xia J., Wang X., Wang X., Zhu C., Ramasse Q.M., Zhang A., An B., Zhang Y., Martí-Sánchez S., Morante J.R., Wang L., Tay B.K., Yakobson B.I., Trampert A., Zhang H., Wu M., Wang Q.J., Arbiol J., Liu Z. Nature Communications; 11 (1, 57) 2020. 10.1038/s41467-019-13631-2. IF: 11.878

    Magnetic Nanostructures | Advanced Electron Nanoscopy

    Atom-thin transition metal dichalcogenides (TMDs) have emerged as fascinating materials and key structures for electrocatalysis. So far, their edges, dopant heteroatoms and defects have been intensively explored as active sites for the hydrogen evolution reaction (HER) to split water. However, grain boundaries (GBs), a key type of defects in TMDs, have been overlooked due to their low density and large structural variations. Here, we demonstrate the synthesis of wafer-size atom-thin TMD films with an ultra-high-density of GBs, up to ~1012 cm−2. We propose a climb and drive 0D/2D interaction to explain the underlying growth mechanism. The electrocatalytic activity of the nanograin film is comprehensively examined by micro-electrochemical measurements, showing an excellent hydrogen-evolution performance (onset potential: −25 mV and Tafel slope: 54 mV dec−1), thus indicating an intrinsically high activation of the TMD GBs. © 2020, The Author(s).

  • Enhancement of organophosphate degradation by electroactive pyrrole and imidazole copolymers

    Hryniewicz B.M., Wolfart F., Gómez-Romero P., Orth E.S., Vidotti M. Electrochimica Acta; 338 (135842) 2020. 10.1016/j.electacta.2020.135842. IF: 5.383

    Novel Energy-Oriented Materials

    Many chemical warfare agents and agrochemicals are composed by organophosphates, that present high toxicity and difficult spontaneous degradation. Amongst the different catalysts to degrade these compounds, heterogeneous systems stand out since they provide easy recovery of the catalyst. However, the limited diffusion of the substrate decreases the rate of the reactions when compared to homogeneous catalysis. To reach a good efficiency in the dephosphorylation, we created heterogeneous catalysts based on pyrrole and imidazole that can enhance the degradation by different effects; both catalytic activity of imidazole and electroactivity of polypyrrole were evaluated. Spectroelectrochemical studies evidenced that the rate constant changes with the applied potential, indicating different reaction mechanisms with the material in the oxidized and neutral states. In summary, a new perspective allying conducting polymers with chemical catalysts was explored. This cooperative effect should be considered in future works concerning the search for new materials to monitor and eliminate organophosphates. © 2020 Elsevier Ltd

  • Enhancement of thermal boundary conductance of metal–polymer system

    Sandell S., Maire J., Chávez-ángel E., Torres C.M.S., Kristiansen H., Zhang Z., He J. Nanomaterials; 10 (4, 670) 2020. 10.3390/nano10040670. IF: 4.034

    Phononic and Photonic Nanostructures

    In organic electronics, thermal management is a challenge, as most organic materials conduct heat poorly. As these devices become smaller, thermal transport is increasingly limited by organic–inorganic interfaces, for example that between a metal and a polymer. However, the mechanisms of heat transport at these interfaces are not well understood. In this work, we compare three types of metal–polymer interfaces. Polymethyl methacrylate (PMMA) films of different thicknesses (1–15 nm) were spin-coated on silicon substrates and covered with an 80 nm gold film either directly, or over an interface layer of 2 nm of an adhesion promoting metal—either titanium or nickel. We use the frequency-domain thermoreflectance (FDTR) technique to measure the effective thermal conductivity of the polymer film and then extract the metal–polymer thermal boundary conductance (TBC) with a thermal resistance circuit model. We found that the titanium layer increased the TBC by a factor of 2, from 59 × 106 W·m−2·K−1 to 115 × 106 W·m−2·K−1, while the nickel layer increased TBC to 139 × 106 W·m−2·K−1. These results shed light on possible strategies to improve heat transport in organic electronic systems. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

  • Experimental Comparison in Sensing Breast Cancer Mutations by Signal on and Signal off Paper-Based Electroanalytical Strips

    Cinti S., Cinotti G., Parolo C., Nguyen E.P., Caratelli V., Moscone D., Arduini F., Merkoci A. Analytical Chemistry; 92 (2): 1674 - 1679. 2020. 10.1021/acs.analchem.9b02560. IF: 6.350

    Nanobioelectronics and Biosensors

    The development of paper-based electroanalytical strips as powerful diagnostic tools has gained a lot of attention within the sensor community. In particular, the detection of nucleic acids in complex matrices represents a trending topic, especially when focused toward the development of emerging technologies, such as liquid biopsy. DNA-based biosensors have been largely applied in this direction, and currently, there are two main approaches based on target/probe hybridization reported in the literature, namely Signal ON and Signal OFF. In this technical note, the two approaches are evaluated in combination with paper-based electrodes, using a single strand DNA relative to H1047R (A3140G) missense mutation in exon 20 in breast cancer as the model target. A detailed comparison among the analytical performances, detection protocol, and cost associated with the two systems is provided, highlighting the advantages and drawbacks depending on the application. The present work is aimed to a wide audience, particularly for those in the field of point-of-care, and it is intended to provide the know-how to manage with the design and development stages, and to optimize the platform for the sensing of nucleic acids using a paper-based detection method. © 2019 American Chemical Society.

  • Exploring phononic properties of two-dimensional materials using machine learning interatomic potentials

    Mortazavi B., Novikov I.S., Podryabinkin E.V., Roche S., Rabczuk T., Shapeev A.V., Zhuang X. Applied Materials Today; 20 (100685) 2020. 10.1016/j.apmt.2020.100685. IF: 8.013

    Theoretical and Computational Nanoscience

    Phononic properties are commonly studied by calculating force constants using the density functional theory (DFT) simulations. Although DFT simulations offer accurate estimations of phonon dispersion relations or thermal properties, but for low-symmetry and nanoporous structures the computational cost quickly becomes very demanding. Moreover, the computational setups may yield nonphysical imaginary frequencies in the phonon dispersion curves, impeding the assessment of phononic properties and the dynamical stability of the considered system. Here, we compute phonon dispersion relations and examine the dynamical stability of a large ensemble of novel materials and compositions. We propose a fast and convenient alternative to DFT simulations which derived from machine-learning interatomic potentials passively trained over computationally efficient ab-initio molecular dynamics trajectories. Our results for diverse two-dimensional (2D) nanomaterials confirm that the proposed computational strategy can reproduce fundamental thermal properties in close agreement with those obtained via the DFT approach. The presented method offers a stable, efficient, and convenient solution for the examination of dynamical stability and exploring the phononic properties of low-symmetry and porous 2D materials. © 2020 Elsevier Ltd

  • Functionalized carbon dots on TiO2 for perovskite photovoltaics and stable photoanodes for water splitting

    Ansón-Casaos A., Hernández-Ferrer J., Vallan L., Xie H., Lira-Cantú M., Benito A.M., Maser W.K. International Journal of Hydrogen Energy; 2020. 10.1016/j.ijhydene.2020.03.077. IF: 4.084

    Nanostructured Materials for Photovoltaic Energy

    Various types of fluorescent carbon nanoparticles, often called carbon dots (CDs), are synthesized by different polycondensation methods: microwave irradiation, hydrothermal conditions or solution chemistry at ambient temperature with subsequent chemical functionalization. The CDs are deposited on TiO2 films to be probed as electron transport layers in perovskite photovoltaics and the anode for photoelectrochemical water splitting. Nitrogen CDs, which do not contain oxygen, lead to an increase of around 50 mV in the open circuit voltage of perovskite solar cells. All the CD types produce an improved photocurrent in water splitting, particularly CDs that are functionalized with thiol groups and butyl chains. It is demonstrated that the modified electrode is stable under continuous operation. Other electrochemical characteristics of the electrode, such as the voltammogram shape, onset potentials and open circuit potentials, remain nearly unchanged upon the deposition of CDs. Only the incident photon to current conversion efficiency improves clearly, extending the absorption range by around 20 nm towards longer wavelengths. This study provides new data about mechanisms and electrode arrangements for improving the performance of n-type semiconductors in photovoltaic cells and photoelectrochemical hydrogen production. © 2020 Hydrogen Energy Publications LLC

  • GaAs nanoscale membranes: Prospects for seamless integration of III-Vs on silicon

    Raya A.M., Friedl M., Martí-Sánchez S., Dubrovskii V.G., Francaviglia L., Alén B., Morgan N., Tütüncüoglu G., Ramasse Q.M., Fuster D., Llorens J.M., Arbiol J., Fontcuberta I Morral A. Nanoscale; 12 (2): 815 - 824. 2020. 10.1039/c9nr08453c. IF: 6.970

    Advanced Electron Nanoscopy

    The growth of compound semiconductors on silicon has been widely sought after for decades, but reliable methods for defect-free combination of these materials have remained elusive. Recently, interconnected GaAs nanoscale membranes have been used as templates for the scalable integration of nanowire networks on III-V substrates. Here, we demonstrate how GaAs nanoscale membranes can be seamlessly integrated on silicon by controlling the density of nuclei in the initial stages of growth. We also correlate the absence or presence of defects with the existence of a single or multiple nucleation regime for the single membranes. Certain defects exhibit well-differentiated spectroscopic features that we identify with cathodoluminescence and micro-photoluminescence techniques. Overall, this work presents a new approach for the seamless integration of compound semiconductors on silicon. © 2019 The Royal Society of Chemistry.

  • Gap anisotropy in multiband superconductors based on multiple scattering theory

    Saunderson T.G., Annett J.F., Újfalussy B., Csire G., Gradhand M. Physical Review B; 101 (6, 064510) 2020. 10.1103/PhysRevB.101.064510. IF: 3.736

    Theory and Simulation

    We implement the Bogoliubov-de Gennes equation in a screened Korringa-Kohn-Rostoker method for solving, self-consistently, the superconducting state for three-dimensional crystals. This method combines the full complexity of the underlying electronic structure and Fermi surface geometry with a simple phenomenological parametrization for the superconductivity. We apply this theoretical framework to the known s-wave superconductors Nb, Pb, and MgB2. In these materials multiple distinct peaks at the gap in the density of states were observed, showing significant gap anisotropy which is in good agreement with experiment. Qualitatively, the results can be explained in terms of the k-dependent Fermi velocities on the Fermi surface sheets exploiting concepts from BCS theory. © 2020 American Physical Society.

  • Graphene related materials for thermal management

    Fu Y., Hansson J., Liu Y., Chen S., Zehri A., Samani M.K., Wang N., Ni Y., Zhang Y., Zhang Z.-B., Wang Q., Li M., Lu H., Sledzinska M., Torres C.M.S., Volz S., Balandin A.A., Xu X., Liu J. 2D Materials; 7 (1, 012001) 2020. 10.1088/2053-1583/ab48d9. IF: 7.343

    Phononic and Photonic Nanostructures

    Almost 15 years have gone ever since the discovery of graphene as a single atom layer. Numerous papers have been published to demonstrate its high electron mobility, excellent thermal and mechanical as well as optical properties. We have recently seen more and more applications towards using graphene in commercial products. This paper is an attempt to review and summarize the current status of the research of the thermal properties of graphene and other 2D based materials including the manufacturing and characterization techniques and their applications, especially in electronics and power modules. It is obvious from the review that graphene has penetrated the market and gets more and more applications in commercial electronics thermal management context. In the paper, we also made a critical analysis of how mature the manufacturing processes are; what are the accuracies and challenges with the various characterization techniques and what are the remaining questions and issues left before we see further more applications in this exciting and fascinating field. © 2019 IOP Publishing Ltd.

  • Graphene triggered enhancement in visible-light active photocatalysis as well as in energy storage capacity of (CFO)1-x(GNPs)x nanocomposites

    Israr M., Iqbal J., Arshad A., Rani M., Gómez‐Romero P., Benages R. Ceramics International; 46 (3): 2630 - 2639. 2020. 10.1016/j.ceramint.2019.09.232. IF: 3.450

    Novel Energy-Oriented Materials

    Cobalt ferrite-graphene nanoplatelets ((CFO)1-x(GNPs)x) nanocomposites are promising for efficient photocatalysis and high-performance supercapacitors. Multifunctional (CFO)1-x(GNPs)x nanocomposites prepared via facile chemical method have been investigated for their physio-chemical characteristics like crystal structure, morphology, chemical composition, optical properties, infrared vibrational modes, photocatalytic and supercapacitor applications. Interestingly, the photocatalytic activity of CFO nanostructures has been improved significantly from 38.3% to 98.7% with the addition of graphene which can be attributed to control over recombination of charge carriers. It is also found that the specific capacitance of the prepared (CFO)1-x(GNPs)x nanocomposite electrode at 0.5 Ag-1 is three times higher than that of only CFO based electrode which could be due to the conducting nature of graphene nanoplatelets (GNPs). The enhanced photocatalytic and improved electrochemical characteristics suggest the effective use of prepared nanocomposites in water purification and supercapacitor nanodevices. © 2019 Elsevier Ltd and Techna Group S.r.l.

  • Grouping all carbon nanotubes into a single substance category is scientifically unjustified

    Fadeel B., Kostarelos K. Nature Nanotechnology; 15 (3): 164. 2020. 10.1038/s41565-020-0654-0. IF: 33.407


    [No abstract available]

  • Hepato(Geno)toxicity assessment of nanoparticles in a hepg2 liver spheroid model

    Elje E., Mariussen E., Moriones O.H., Bastús N.G., Puntes V., Kohl Y., Dusinska M., Rundén-Pran E. Nanomaterials; 10 (3, 545) 2020. 10.3390/nano10030545. IF: 4.034

    Inorganic Nanoparticles

    (1) In compliance with the 3Rs policy to reduce, refine and replace animal experiments, the development of advanced in vitro models is needed for nanotoxicity assessment. Cells cultivated in 3D resemble organ structures better than 2D cultures. This study aims to compare cytotoxic and genotoxic responses induced by titanium dioxide (TiO2), silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) in 2D monolayer and 3D spheroid cultures of HepG2 human liver cells. (2) NPs were characterized by electron microscopy, dynamic light scattering, laser Doppler anemometry, UV-vis spectroscopy and mass spectrometry. Cytotoxicity was investigated by the alamarBlue assay and confocal microscopy in HepG2 monolayer and spheroid cultures after 24 h of NP exposure. DNA damage (strand breaks and oxidized base lesions) was measured by the comet assay. (3) Ag-NPs were aggregated at 24 h, and a substantial part of the ZnO-NPs was dissolved in culture medium. Ag-NPs induced stronger cytotoxicity in 2D cultures (EC50 3.8 µg/cm2) than in 3D cultures (EC50 > 30 µg/cm2), and ZnO-NPs induced cytotoxicity to a similar extent in both models (EC50 10.1–16.2 µg/cm2). Ag-and ZnO-NPs showed a concentration-dependent genotoxic effect, but the effect was not statistically significant. TiO2-NPs showed no toxicity (EC50 > 75 µg/cm2). (4) This study shows that the HepG2 spheroid model is a promising advanced in vitro model for toxicity assessment of NPs. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

  • Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks: The case of squaramide

    Broto-Ribas A., Vignatti C., Jimenez-Almarza A., Luis-Barrera J., Dolatkhah Z., Gándara F., Imaz I., Mas-Ballesté R., Alemán J., Maspoch D. Nano Research; 2020. 10.1007/s12274-020-2779-8. IF: 8.515

    Supramolecular NanoChemistry and Materials

    A well-established strategy to synthesize heterogeneous, metal-organic framework (MOF) catalysts that exhibit nanoconfinement effects, and specific pores with highly-localized catalytic sites, is to use organic linkers containing organocatalytic centers. Here, we report that by combining this linker approach with reticular chemistry, and exploiting three-dimensioanl (3D) MOF-structural data from the Cambridge Structural Database, we have designed four heterogeneous MOF-based catalysts for standard organic transformations. These programmable MOFs are isoreticular versions of pcu IRMOF-16, fcu UiO-68 and pillared-pcu SNU-8X, the three most common topologies of MOFs built from the organic linker p,p’-terphenyldicarboxylic acid (tpdc). To synthesize the four squaramide-based MOFs, we designed and synthesized a linker, 4,4’-((3,4‐dioxocyclobut‐1‐ene‐1,2‐diyl)bis(azanedyil))dibenzoic acid (Sq_tpdc), which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers. Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena. Therefore, the four MOFs share the same organocatalytic squaramide moiety, but confine it within distinct pore environments. We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations: a Friedel-Crafts alkylation and an epoxide ring-opening. Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences. [Figure not available: see fulltext.] © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.

  • Highly Loaded Mildly Edge-Oxidized Graphene Nanosheet Dispersions for Large-Scale Inkjet Printing of Electrochemical Sensors

    Nagar B., Jović M., Bassetto V.C., Zhu Y., Pick H., Gómez-Romero P., Merkoçi A., Girault H.H., Lesch A. ChemElectroChem; 7 (2): 460 - 468. 2020. 10.1002/celc.201901697. IF: 3.975

    Novel Energy-Oriented Materials | Nanobioelectronics and Biosensors

    Inkjet printing of electrochemical sensors using a highly loaded mildly edge-oxidized graphene nanosheet (EOGN) ink is presented. An ink with 30 mg/mL EOGNs is formulated in a mixture of N-methyl pyrrolidone and propylene glycol with only 30 min of sonication. The absence of additives, such as polymeric stabilizers or surfactants, circumvents reduced electrochemical activity of coated particles and avoids harsh post-printing conditions for additive removal. A single light pulse from a xenon flash lamp dries the printed EGON film within a fraction of a second and creates a compact electrode surface. An accurate coverage with only 30.4 μg of EOGNs per printed layer and cm2 is achieved. The EOGN films adhere well to flexible polyimide substrates in aqueous solution. Electrochemical measurements were performed using cyclic voltammetry and differential pulse voltammetry. An all inkjet-printed three-electrode living bacterial cell detector is prepared with EOGN working and counter electrodes and silver-based quasi-reference electrode. The presence of E. coli in liquid samples is recorded with four electroactive metabolic activity indicators. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Highly reduced ecotoxicity of ZnO-based micro/nanostructures on aquatic biota: Influence of architecture, chemical composition, fixation, and photocatalytic efficiency

    Serrà A., Zhang Y., Sepúlveda B., Gómez E., Nogués J., Michler J., Philippe L. Water Research; 169 (115210) 2020. 10.1016/j.watres.2019.115210. IF: 7.913

    Magnetic Nanostructures

    Developing efficient sunlight photocatalysts with enhanced photocorrosion resistance and minimal ecotoxicological effects on aquatic biota is critical to combat water contamination. Here, the role of chemical composition, architecture, and fixation on the ecotoxicological effects on microalgae of different ZnO and ZnO@ZnS based water decontamination photocatalysts was analyzed in depth. In particular, the ecotoxicological effects of films, nanoparticles and biomimetic micro/nano-ferns were carefully assessed by correlating the algae's viability to the Zn(II) release, the photocatalyst–microalgae interaction, and the production of reactive oxygen species (ROS). The results showed a drastic improvement in algal viability for supported ZnO@ZnS core@shell micro/nanoferns, as their ecotoxicity after 96 h light exposure was significantly lower (3.7–10.0% viability loss) compared to the ZnO films (18.4–35.5% loss), ZnO micro/nanoferns (28.5–53.5% loss), ZnO nanoparticles (48.3–91.7% loss) or ZnO@ZnS nanoparticles (8.6–19.2% loss) for catalysts concentrations ranging from 25 mg L−1 to 400 mg L−1. In particular, the ZnO@ZnS micro/nanoferns with a concentration of 400 mg L−1 exhibited excellent photocatalytic efficiency to mineralize a multi-pollutant solution (81.4 ± 0.3% mineralization efficiency after 210 min under UV-filtered visible light irradiation) and minimal photocorrosion (<5% of photocatalyst dissolution after 96 h of UV-filtered visible light irradiation). Remarkably, the ZnO@ZnS micro/nanoferns showed lower loss of algal viability (9.8 ± 1.1%) after 96 h of light exposure, with minimal reduction in microalgal biomass (9.1 ± 1.0%), as well as in the quantity of chlorophyll-a (9.5 ± 1.0%), carotenoids (8.6 ± 0.9%) and phycocyanin (5.6 ± 0.6%). Altogether, the optimized ZnO@ZnS core@shell micro/nanoferns represent excellent ecofriendly photocatalysts for water remediation in complex media, as they combine enhanced sunlight remediation efficiency, minimal adverse effects on biological microorganisms, high reusability and easy recyclability. © 2019 Elsevier Ltd

  • Hybrid Ni@ZnO@ZnS-Microalgae for Circular Economy: A Smart Route to the Efficient Integration of Solar Photocatalytic Water Decontamination and Bioethanol Production

    Serrà A., Artal R., García-Amorós J., Sepúlveda B., Gómez E., Nogués J., Philippe L. Advanced Science; 7 (3, 1902447) 2020. 10.1002/advs.201902447. IF: 15.804

    Magnetic Nanostructures

    Water remediation and development of carbon-neutral fuels are a priority for the evermore industrialized society. The answer to these challenges should be simple, sustainable, and inexpensive. Thus, biomimetic-inspired circular and holistic processes combing water remediation and biofuel production can be an appealing concept to deal with these global issues. A simple circular approach using helical Spirulina platensis microalgae as biotemplates to synthesize Ni@ZnO@ZnS photocatalysts for efficient solar water decontamination and bioethanol production during the recycling process is presented. Under solar irradiation, the Ni@ZnO@ZnS-Spirulina photocatalyst exhibits enhanced activity (mineralization efficiency >99%) with minimal photocorrosion and excellent reusability. At the end of its effective lifetime for water remediation, the microalgae skeleton (mainly glycogen and glucose) of the photocatalyst is recycled to directly produce bioethanol by simultaneous saccharification and fermentation process. An outstanding ethanol yield of 0.4 L kg−1, which is similar to the highest yield obtained from oxygenic photosynthetic microorganisms, is obtained. Thus, the entire process allows effective solar photocatalytic water remediation and bioethanol production at room temperature using simple and easily scalable procedures that simultaneously fixes carbon dioxide, thereby constituting a zero-carbon-emission circular process. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Impact of synthetic conditions on the anisotropic thermal conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT): A molecular dynamics investigation

    Cappai A., Antidormi A., Bosin A., Narducci D., Colombo L., Melis C. Physical Review Materials; 4 (3, 035401) 2020. 10.1103/PhysRevMaterials.4.035401. IF: 2.926

    Theoretical and Computational Nanoscience

    In this work we study the effect of different synthetic conditions on thermal transport properties of poly(3,4-ethylenedioxythiophene) (PEDOT) by focusing in particular on the role of proton scavengers. To this aim, different PEDOT samples were generated in silico using a novel computational algorithm based on a combination of first-principles density functional theory and classical molecular dynamics simulations. The corresponding thermal conductivities were then estimated using the approach to equilibrium molecular dynamics methodology. The results show that the initial synthetic conditions strongly affect the corresponding thermal conductivities, which display variations up to a factor of ∼2 depending on the proton scavenger. By decomposing the thermal conductivity tensor along the direction of maximum chain alignment and the corresponding perpendicular directions, we attribute the thermal conductivity differences to the variations in the average polymer chain length λave. A dependence of the thermal conductivity with the polydispersity index was finally observed, suggesting a possible role of intercrystallite chains in enhancing thermal transport properties. By means of the Green-Kubo modal analysis, we eventually characterize the vibrational modes involved in PEDOT thermal transport and investigate how they are related to the thermal conductivity values of the samples. © 2020 American Physical Society.

  • Improved metal-graphene contacts for low-noise, high-density microtransistor arrays for neural sensing

    Schaefer N., Garcia-Cortadella R., Calia A.B., Mavredakis N., Illa X., Masvidal-Codina E., Cruz J.D.L., Corro E.D., Rodríguez L., Prats-Alfonso E., Bousquet J., Martínez-Aguilar J., Pérez-Marín A.P., Hébert C., Villa R., Jiménez D., Guimerà-Brunet A., Garrido J.A. Carbon; 161: 647 - 655. 2020. 10.1016/j.carbon.2020.01.066. IF: 7.466

    Advanced Electronic Materials and Devices

    Poor metal contact interfaces are one of the main limitations preventing unhampered access to the full potential of two-dimensional materials in electronics. Here we present graphene solution-gated field-effect-transistors (gSGFETs) with strongly improved linearity, homogeneity and sensitivity for small sensor sizes, resulting from ultraviolet ozone (UVO) contact treatment. The contribution of channel and contact region to the total device conductivity and flicker noise is explored experimentally and explained with a theoretical model. Finally, in-vitro recordings of flexible microelectrocorticography (μ-ECoG) probes were performed to validate the superior sensitivity of the UVO-treated gSGFET to brain-like activity. These results connote an important step towards the fabrication of high-density gSGFET μ-ECoG arrays with state-of-the-art sensitivity and homogeneity, thus demonstrating the potential of this technology as a versatile platform for the new generation of neural interfaces. © 2020 Elsevier Ltd

  • Increasing complexity of nanocrystals

    Bastús N.G., Gonzalez E., Puntes V. Nano Today; 32 (100859) 2020. 10.1016/j.nantod.2020.100859. IF: 16.582

    Inorganic Nanoparticles

    [No abstract available]

  • Inkjet-printed electrochemically reduced graphene oxide microelectrode as a platform for HT-2 mycotoxin immunoenzymatic biosensing

    Kudr J., Zhao L., Nguyen E.P., Arola H., Nevanen T.K., Adam V., Zitka O., Merkoçi A. Biosensors and Bioelectronics; 156 (112109) 2020. 10.1016/j.bios.2020.112109. IF: 9.518

    Nanobioelectronics and Biosensors

    The design and application of an inkjet-printed electrochemically reduced graphene oxide microelectrode for HT-2 mycotoxin immunoenzymatic biosensing is reported. A water-based graphene oxide ink was first formulated and single-drop line working microelectrodes were inkjet-printed onto poly(ethylene 2,6-naphthalate) substrates, with dimensions of 78 μm in width and 30 nm in height after solvent evaporation. The printed graphene oxide microelectrodes were electrochemically reduced and characterized by Raman and X-ray photoelectron spectroscopies in addition to microscopies. Through optimization of the electrochemical reduction parameters, differential pulse voltammetry were performed to examine the sensing of 1-naphthol (1-N), where it was revealed that reduction times had significant effects on electrode performance. The developed microelectrodes were then used as an immunoenzymatic biosensor for the detection of HT-2 mycotoxin based on carbodiimide linking of the microelectrode surface and HT-2 toxin antigen binding fragment of antibody (anti-HT2 (10) Fab). The HT-2 toxin and anti-HT2 (10) Fab reaction was reported by anti-HT2 immune complex single-chain variable fragment of antibody fused with alkaline phosphatase (anti-IC-HT2 scFv-ALP) which is able to produce an electroactive reporter – 1-N. The biosensor showed detection limit of 1.6 ng ∙ mL−1 and a linear dynamic range of 6.3 – 100.0 ng ∙ mL−1 within a 5 min incubation with 1-naphthyl phosphate (1-NP) substrate. © 2020 Elsevier B.V.

  • Investigation of The Cellular Response to Bone Fractures: Evidence for Flexoelectricity

    Núñez-Toldrà R., Vasquez-Sancho F., Barroca N., Catalan G. Scientific Reports; 10 (1, 254) 2020. 10.1038/s41598-019-57121-3. IF: 4.011

    Oxide Nanophysics

    The recent discovery of bone flexoelectricity (strain-gradient-induced electrical polarization) suggests that flexoelectricity could have physiological effects in bones, and specifically near bone fractures, where flexoelectricity is theoretically highest. Here, we report a cytological study of the interaction between crack stress and bone cells. We have cultured MC3T3-E1 mouse osteoblastic cells in biomimetic microcracked hydroxyapatite substrates, differentiated into osteocytes and applied a strain gradient to the samples. The results show a strong apoptotic cellular response, whereby mechanical stimulation causes those cells near the crack to die, as indicated by live-dead and caspase staining. In addition, analysis two weeks post-stimulation shows increased cell attachment and mineralization around microcracks and a higher expression of osteocalcin –an osteogenic protein known to be promoted by physical exercise. The results are consistent with flexoelectricity playing at least two different roles in bone remodelling: apoptotic trigger of the repair protocol, and electro-stimulant of the bone-building activity of osteoblasts. © 2020, The Author(s).

  • Ion bombardment induced formation of self-organized wafer-scale GaInP nanopillar assemblies

    Visser D., Jaramillo-Fernandez J., Haddad G., Sotomayor Torres C.M., Anand S. Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics; 38 (1, 012801) 2020. 10.1116/1.5127265. IF: 1.351

    Phononic and Photonic Nanostructures

    Ion sputtering assisted formation of nanopillars is demonstrated as a wafer-scale, lithography-free fabrication method to obtain high optical quality gallium indium phosphide (GaInP) nanopillars. Compared to binary materials, little has been reported on the formation of self-organized ternary nanostructures. Epitaxial (100) Ga0.51In0.49P layers lattice matched to GaAs were sputtered by nitrogen (N2) ions with relatively low ion beam energies (∼400 eV) to reduce ion bombardment induced damage. The influence of process parameters such as temperature, sputter duration, ion beam energy, and ion beam incidence angle on the pillar formation is investigated. The fabricated GaInP nanopillars have average diameters of ∼75-100 nm, height of ∼220 nm, and average density of ∼2-4 × 108 pillars/cm2. The authors show that the ion beam incidence angle plays an important role in pillar formation and can be used to tune the pillar shape, diameter, and spatial density. Specifically, tapered to near cylindrical pillar profiles together with a reduction in their average diameters are obtained by varying the ion beam incidence angle from 0° to 20°. A tentative model for the GaInP nanopillar formation is proposed based on transmission electron microscopy and chemical mapping analysis. μ-Photoluminescence and μ-Raman measurements indicate a high optical quality of the c-GaInP nanopillars. © 2019 Author(s).

  • James F. Scott (1942-2020)

    Catalan G., Dawber M., Gregg M., Morrison F., Ramesh R., Zubko P. Nature materials; 19 (6): 580. 2020. 10.1038/s41563-020-0692-x. IF: 38.887

    Oxide Nanophysics

    [No abstract available]

  • Lab in a Tube: Point-of-Care Detection of Escherichia coli

    Amin N., Torralba A.S., Álvarez-Diduk R., Afkhami A., Merkoçi A. Analytical Chemistry; 92 (6): 4209 - 4216. 2020. 10.1021/acs.analchem.9b04369. IF: 6.350

    Nanobioelectronics and Biosensors

    Significant levels of infectious diseases caused by pathogenic bacteria are nowadays a worldwide matter, carrying considerable public health care challenges and huge economic concerns. Because of the rapid transmission of these biothreat agents and the outbreak of diseases, a rapid detection of pathogens in early stages is crucial, particularly in low-resources settings. To this aim, we developed for the first time a new sensing approach carried out in a single step for Escherichia coli O157:H7 detection. The detection principle is based on Förster resonance energy transfer using gold nanoclusters as a signal reporter and gold nanoparticles conjugated with antibodies as a quencher. The sensing platform includes an ultraviolet-light-emitting diode to provide the proper excitation and consists of a microtube containing two pieces of fiber glass; one of them is embedded with label-free gold nanoclusters and the other one with gold nanoparticles conjugated with antibodies. Upon the addition of the sample containing bacteria, the florescence of gold nanoclusters is recovered. The assay was evaluated by the naked eye (on/off) and quantitatively with use of a smartphone camera. The biosensor proved to be highly specific and sensitive, achieving a limit of detection as low as 4.0 cfu mL-1. Additionally, recoveries of 110% and 95% were obtained when the platforms in spiked river and tap water, respectively, were evaluated. Copyright © 2020 American Chemical Society.

  • Label-free detection of nosocomial bacteria using a nanophotonic interferometric biosensor

    Maldonado J., Estévez M.-C., Fernández-Gavela A., González-López J.J., González-Guerrero A.B., Lechuga L.M. Analyst; 145 (2): 497 - 506. 2020. 10.1039/c9an01485c. IF: 4.019

    NanoBiosensors and Bioanalytical Applications

    Nosocomial infections are a major concern at the worldwide level. Early and accurate identification of nosocomial pathogens is crucial to provide timely and adequate treatment. A prompt response also prevents the progression of the infection to life-threatening conditions, such as septicemia or generalized bloodstream infection. We have implemented two highly sensitive methodologies using an ultrasensitive photonic biosensor based on a bimodal waveguide interferometer (BiMW) for the fast detection of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), two of the most prevalent bacteria associated with nosocomial infections. For that, we have developed a biofunctionalization strategy based on the use of a PEGylated silane (silane-PEG-COOH) which provides a highly resistant and bacteria-repelling surface, which is crucial to specifically detect each bacterium. Two different biosensor assays have been set under standard buffer conditions: One based on a specific direct immunoassay employing polyclonal antibodies for the detection of P. aeruginosa and another one employing aptamers for the direct detection of MRSA. The biosensor immunoassay for P. aeruginosa is fast (it only takes 12 min) and specific and has experimentally detected concentrations down to 800 cfu mL-1 (cfu: Colony forming unit). The second one relies on the use of an aptamer that specifically detects penicillin-binding protein 2a (PBP2a), a protein only expressed in the MRSA mutant, providing a photonic biosensor with the ability to identify the resistant pathogen MRSA and differentiate it from methicillin-susceptible S. aureus (MSSA). Direct, label-free, and selective detection of whole MRSA bacteria has been achieved, making possible the direct detection of also 800 cfu mL-1. According to the signal-to-noise (S/N) ratio of the device, a theoretical limit of detection (LOD) of around 49 and 29 cfu mL-1 was estimated for P. aeruginosa and MRSA, respectively. Both results obtained under standard conditions reveal the great potential this interferometric biosensor device has as a versatile and specific tool for bacterial detection and quantification, providing a rapid method for the identification of nosocomial pathogens within the clinical requirements of sensitivity for the diagnosis of infections. © 2020 The Royal Society of Chemistry.

  • Low-frequency noise parameter extraction method for single-layer graphene FETs

    Mavredakis N., Wei W., Pallecchi E., Vignaud D., Happy H., Cortadella R.G., Schaefer N., Calia A.B., Garrido J.A., Jimenez D. IEEE Transactions on Electron Devices; 67 (5, 9042866): 2093 - 2099. 2020. 10.1109/TED.2020.2978215. IF: 2.704

    Advanced Electronic Materials and Devices

    In this article, a detailed parameter extraction methodology is proposed for low-frequency noise (LFN) in single-layer (SL) graphene transistors (GFETs) based on a recently established compact LFN model. The drain current and LFN of two short channel back-gated GFETs (L = 300 and 100 nm) were measured at lower and higher drain voltages, for a wide range of gate voltages covering the region away from charge neutrality point (CNP) up to CNP at p-type operation region. Current-voltage (IV) and LFN data were also available from a long-channel SL top solution-gated (SG) GFET (L = 5 μm), for both p- and n-type regions near and away CNP. At each of these regimes, the appropriate IV and LFN parameters can be accurately extracted. Regarding LFN, mobility fluctuation effect is dominant at CNP, and from there, the Hooge parameter αH can be extracted, whereas the carrier number fluctuation contribution which is responsible for the well-known M-shape bias dependence of output noise divided by squared drain current, also observed in our data, makes possible the extraction of the NT parameter related to the number of traps. In the less possible case of a Λ-shape trend, NT and αH can be extracted simultaneously from the region near CNP. Away from CNP, contact resistance can have a significant contribution to LFN, and from there, the relevant parameter SΔ R2 is defined. The LFN parameters described above can be estimated from the low drain voltage region of operation where the effect of velocity saturation (VS) mechanism is negligible. VS effect results in the reduction of LFN at higher drain voltages, and from there, the IV parameter hΩ which represents the phonon energy and is related to VS effect can be derived both from drain current and LFN data. © 1963-2012 IEEE.

  • Magnetic proximity in a van der Waals heterostructure of magnetic insulator and graphene

    Karpiak B., Cummings A.W., Zollner K., Vila M., Khokhriakov D., Hoque A.M., Dankert A., Svedlindh P., Fabian J., Roche S., Dash S.P. 2D Materials; 7 (1, 015026) 2020. 10.1088/2053-1583/ab5915. IF: 7.343

    Theoretical and Computational Nanoscience

    Engineering 2D material heterostructures by combining the best of different materials in one ultimate unit can offer a plethora of opportunities in condensed matter physics. Here, in the van der Waals heterostructures of the ferromagnetic insulator Cr2Ge2Te6 and graphene, our observations indicate an out-of-plane proximity-induced ferromagnetic exchange interaction in graphene. The perpendicular magnetic anisotropy of Cr2Ge2Te6 results in significant modification of the spin transport and precession in graphene, which can be ascribed to the proximity-induced exchange interaction. Furthermore, the observation of a larger lifetime for perpendicular spins in comparison to the in-plane counterpart suggests the creation of a proximity-induced anisotropic spin texture in graphene. Our experimental results and density functional theory calculations open up opportunities for the realization of proximity-induced magnetic interactions and spin filters in 2D material heterostructures and can form the basic building blocks for future spintronic and topological quantum devices. © 2019 IOP Publishing Ltd.

  • MOF-Beads Containing Inorganic Nanoparticles for the Simultaneous Removal of Multiple Heavy Metals from Water

    Boix G., Troyano J., Garzón-Tovar L., Camur C., Bermejo N., Yazdi A., Piella J., Bastus N.G., Puntes V.F., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 12 (9): 10554 - 10562. 2020. 10.1021/acsami.9b23206. IF: 8.456

    Supramolecular NanoChemistry and Materials | Inorganic Nanoparticles

    Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile, and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein, we report the complementary adsorption capacities of metal-organic frameworks (here, UiO-66 and UiO-66-(SH)2) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II), and Hg(II). We further show that these microbeads can be used as a packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spray-drying technique to simultaneously incorporate two types of iNPs (CeO2 and Fe3O4) into UiO-66-(SH)2, obtaining CeO2/Fe3O4@UiO-66-(SH)2 microbeads that adsorb heavy metals and are magnetically responsive. Copyright © 2020 American Chemical Society.

  • Molecular Approach for Engineering Interfacial Interactions in Magnetic/Topological Insulator Heterostructures

    Cuxart M.G., Valbuena M.A., Robles R., Moreno C., Bonell F., Sauthier G., Imaz I., Xu H., Nistor C., Barla A., Gargiani P., Valvidares M., Maspoch D., Gambardella P., Valenzuela S.O., Mugarza A. ACS Nano; 14 (5): 6285 - 6294. 2020. 10.1021/acsnano.0c02498. IF: 13.903

    Supramolecular NanoChemistry and Materials | Physics and Engineering of Nanodevices | Atomic Manipulation and Spectroscopy

    Controlling interfacial interactions in magnetic/topological insulator heterostructures is a major challenge for the emergence of novel spin-dependent electronic phenomena. As for any rational design of heterostructures that rely on proximity effects, one should ideally retain the overall properties of each component while tuning interactions at the interface. However, in most inorganic interfaces, interactions are too strong, consequently perturbing, and even quenching, both the magnetic moment and the topological surface states at each side of the interface. Here, we show that these properties can be preserved using ligand chemistry to tune the interaction of magnetic ions with the surface states. By depositing Co-based porphyrin and phthalocyanine monolayers on the surface of Bi2Te3 thin films, robust interfaces are formed that preserve undoped topological surface states as well as the pristine magnetic moment of the divalent Co ions. The selected ligands allow us to tune the interfacial hybridization within this weak interaction regime. These results, which are in stark contrast with the observed suppression of the surface state at the first quintuple layer of Bi2Se3 induced by the interaction with Co phthalocyanines, demonstrate the capability of planar metal-organic molecules to span interactions from the strong to the weak limit. © 2020 American Chemical Society.

  • Monodisperse CoSn and NiSn Nanoparticles Supported on Commercial Carbon as Anode for Lithium- And Potassium-Ion Batteries

    Li J., Xu X., Yu X., Han X., Zhang T., Zuo Y., Zhang C., Yang D., Wang X., Luo Z., Arbiol J., Llorca J., Liu J., Cabot A. ACS Applied Materials and Interfaces; 12 (4): 4414 - 4422. 2020. 10.1021/acsami.9b16418. IF: 8.456

    Advanced Electron Nanoscopy

    Monodisperse CoSn and NiSn nanoparticles were prepared in solution and supported on commercial carbon black. The obtained nanocomposites were applied as anodes for Li- and K-ion batteries. CoSn@C delivered stable average capacities of 850, 650, and 500 mAh g-1 at 0.2, 1.0, and 2.0 A g-1, respectively, well above those of commercial graphite anodes. The capacity of NiSn@C retained up to 575 mAh g-1 at a current of 1.0 A g-1 over 200 continuous cycles. Up to 74.5 and 69.7% pseudocapacitance contributions for Li-ion batteries were measured for CoSn@C and NiSn@C, respectively, at 1.0 mV s-1. CoSn@C was further tested in full-cell lithium-ion batteries with a LiFePO4 cathode to yield a stable capacity of 350 mAh g-1 at a rate of 0.2 A g-1. As electrode in K-ion batteries, CoSn@C composites presented a stable capacity of around 200 mAh g-1 at 0.2 A g-1 over 400 continuous cycles, and NiSn@C delivered a lower capacity of around 100 mAh g-1 over 300 cycles. Copyright © 2020 American Chemical Society.

  • Multi-approach analysis to assess the chromium(III) immobilization by Ochrobactrum anthropi DE2010

    Villagrasa E., Ballesteros B., Obiol A., Millach L., Esteve I., Solé A. Chemosphere; 238 (124663) 2020. 10.1016/j.chemosphere.2019.124663. IF: 5.108

    Electron Microscopy Unit

    Ochrobactrum anthropi DE2010 is a microorganism isolated from Ebro Delta microbial mats and able to resist high doses of chromium(III) due to its capacity to tolerate, absorb and accumulate this metal. The effect of this pollutant on O. anthropi DE2010 has been studied assessing changes in viability and biomass, sorption yields and removal efficiencies. Furthermore, and for the first time, its capacity for immobilizing Cr(III) from culture media was tested by a combination of High Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM) imaging coupled to Energy Dispersive X-ray spectroscopy (EDX). The results showed that O. anthropi DE2010 was grown optimally at 0–2 mM Cr(III). On the other hand, from 2 to 10 mM Cr(III) microbial plate counts, growth rates, cell viability, and biomass decreased while extracellular polymeric substances (EPS) production increases. Furthermore, this bacterium had a great ability to remove Cr(III) at 10 mM (q = 950.00 mg g−1) immobilizing it mostly in bright polyphosphate inclusions and secondarily on the cellular surface at the EPS level. Based on these results, O. anthropi DE2010 could be considered as a potential agent for bioremediation in Cr(III) contaminated environments. © 2019 Elsevier Ltd

  • Multiplexed neural sensor array of graphene solution-gated field-effect transistors

    Schaefer N., Garcia-Cortadella R., Martínez-Aguilar J., Schwesig G., Illa X., Moya Lara A., Santiago S., Hébert C., Guirado G., Villa R., Sirota A., Guimerà-Brunet A., Garrido J.A. 2D Materials; 7 (2, 025046) 2020. 10.1088/2053-1583/ab7976. IF: 7.343

    Advanced Electronic Materials and Devices

    Electrocorticography (ECoG) is a well-established technique to monitor electrophysiological activity from the surface of the brain and has proved crucial for the current generation of neural prostheses and brain-computer interfaces. However, existing ECoG technologies still fail to provide the resolution necessary to accurately map highly localized activity across large brain areas, due to the rapidly increasing size of connector footprint with sensor count. This work demonstrates the use of a flexible array of graphene solution-gated field-effect transistors (gSGFET), exploring the concept of multiplexed readout using an external switching matrix. This approach does not only allow for an increased sensor count, but due to the use of active sensing devices (i.e. transistors) over microelectrodes it makes additional buffer transistors redundant, which drastically eases the complexity of device fabrication on flexible substrates. The presented results pave the way for upscaling the gSGFET technology towards large-scale, high-density μECoG-arrays, eventually capable of resolving neural activity down to a single neuron level, while simultaneously mapping large brain regions. © 2020 IOP Publishing Ltd.

  • Nano-lantern on paper for smartphone-based ATP detection

    Calabretta M.M., Álvarez-Diduk R., Michelini E., Roda A., Merkoçi A. Biosensors and Bioelectronics; 150 (111902) 2020. 10.1016/j.bios.2019.111902. IF: 9.518

    Nanobioelectronics and Biosensors

    ATP-driven bioluminescence relying on the D-luciferin-luciferase reaction is widely employed for several biosensing applications where bacterial ATP detection allows to verify microbial contamination for hygiene monitoring in hospitals, food processing and in general for cell viability studies. Several ATP kit assays are already commercially available but an user-friendly ATP biosensor characterized by low-cost, portability, and adequate sensitivity would be highly valuable for rapid and facile on site screening. Thanks to an innovative freeze-drying procedure, we developed a user-friendly, ready-to-use and stable ATP sensing paper biosensor that can be combined with smartphone detection. The ATP sensing paper includes a lyophilized “nano-lantern” with reaction components being rapidly reconstituted by 10 μL sample addition, enabling detection of 10−14 mol of ATP within 10 min. We analysed urinary microbial ATP as a biomarker of urinary tract infection (UTI), confirming the capability of the ATP sensing paper to detect the threshold for positivity corresponding to 105 colony-forming units of bacteria per mL of urine. © 2019 Elsevier B.V.

  • Nanomaterials for Nanotheranostics: Tuning Their Properties According to Disease Needs

    Wong X.Y., Sena-Torralba A., Álvarez-Diduk R., Muthoosamy K., Merkoçi A. ACS Nano; 14 (3): 2585 - 2627. 2020. 10.1021/acsnano.9b08133. IF: 13.903

    Nanobioelectronics and Biosensors

    Nanotheranostics is one of the biggest scientific breakthroughs in nanomedicine. Most of the currently available diagnosis and therapies are invasive, time-consuming, and associated with severe toxic side effects. Nanotheranostics, on the other hand, has the potential to bridge this gap by harnessing the capabilities of nanotechnology and nanomaterials for combined therapeutics and diagnostics with markedly enhanced efficacy. However, nanomaterial applications in nanotheranostics are still in its infancy. This is due to the fact that each disease has a particular microenvironment with well-defined characteristics, which promotes deeper selection criteria of nanomaterials to meet the disease needs. In this review, we have outlined how nanomaterials are designed and tailored for nanotheranostics of cancer and other diseases such as neurodegenerative, autoimmune (particularly on rheumatoid arthritis), and cardiovascular diseases. The penetrability and retention of a nanomaterial in the biological system, the therapeutic strategy used, and the imaging mode selected are some of the aspects discussed for each disease. The specific properties of the nanomaterials in terms of feasibility, physicochemical challenges, progress in clinical trials, its toxicity, and their future application on translational medicine are addressed. Our review meticulously and critically examines the applications of nanotheranostics with various nanomaterials, including graphene, across several diseases, offering a broader perspective of this emerging field. © 2020 American Chemical Society.

  • Nanoparticle-based lateral flow assays

    Calucho E., Parolo C., Rivas L., Álvarez-Diduk R., Merkoçi A. Comprehensive Analytical Chemistry; 2020. 10.1016/bs.coac.2020.04.011. IF: 0.000

    Nanobioelectronics and Biosensors

    Lateral flow assays (LFAs) are paper-based analytical devices that allow for the performance of in situ diagnostic tests with good sensitivity, specificity, repeatability and low limit of detection. The application of different kinds of nanoparticles with different properties have made LFAs compatible with different detection methods (e.g. colorimetry, photoluminescence, magnetism, heating, electroactivity), thus showing their versatility. Even though LFA technology is well-established, research on the topic is more alive than ever due to the advances in the study of nanomaterials, the implementation of smartphone technology for signal readout and the creativity in finding new strategies for signal enhancement. In this chapter, the applications of LFAs using different kind of nanoparticles as labels are compiled, demonstrating their use in a range of fields such as clinical diagnostics, environmental monitoring, food safety and veterinary. Given the relevance of nanoparticles in the performance of LFAs, a section of the chapter is dedicated to biofunctionalisation strategies. © 2020 Elsevier B.V.

  • Nanoscale coordination polymers for medicine and sensors

    Solórzano R., Suárez-García S., Novio F., Lorenzo J., Alibés R., Busqué F., Ruiz-Molina D. Advances in Inorganic Chemistry; 2020. 10.1016/bs.adioch.2020.03.001. IF: 2.300

    Nanostructured Functional Materials

    Miniaturization of coordination polymers to the nanoscale represents a unique opportunity to assemble a novel class of highly customizable functional materials that marry the rich diversity, chemistry and properties of coordination complexes to the advantages of nanomaterials. The new structures, which exhibit well-defined and dispersed morphologies, can allow for a proper correlation with their functionality, and therefore, enable the rational design of new generations of these nanostructures targeting specific desired properties. In this chapter we will give a brief introduction to the rational fabrication of such functional nanostructures following different coordination polymerization mechanisms. The novel “smart” nanoscale coordination polymer particles (NCPs) exhibit interesting properties of relevance for different fields and applications, worth to mention nanomedicine and sensors. Herein we make a summary of the main results obtained in both areas that evidence the significance of this novel family of materials. For this, the review has been divided into two main sections. In the first part we revise general methodologies for cargo loading and delivery, including the design of stimuli-responsive systems. In the second section we will review the latest advances in the use of NCPs as chemical sensing platforms. These results open new avenues for all the possible applications that can be derived from the implications of CPPs on surfaces. Finally, a brief introduction to the new research line on 2D-coordination polymers will be outlined. © 2020 Elsevier Inc.

  • Nanoscale nights of COVID-19

    Kostarelos K. Nature Nanotechnology; 15 (5): 343 - 344. 2020. 10.1038/s41565-020-0687-4. IF: 33.407


    [No abstract available]

  • Neutral Organic Radical Formation by Chemisorption on Metal Surfaces

    Ajayakumar M.R., Moreno C., Alcón I., Illas F., Rovira C., Veciana J., Bromley S.T., Mugarza A., Mas-Torrent M. Journal of Physical Chemistry Letters; 11 (10): 3897 - 3904. 2020. 10.1021/acs.jpclett.0c00269. IF: 7.329

    Atomic Manipulation and Spectroscopy

    Organic radical monolayers (r-MLs) bonded to metal surfaces are potential materials for the development of molecular (spin)electronics. Typically, stable radicals bearing surface anchoring groups are used to generate r-MLs. Following a recent theoretical proposal based on a model system, we report the first experimental realization of a metal surface-induced r-ML, where a rationally chosen closed-shell precursor 3,5-dichloro-4-[bis(2,4,6-trichlorophenyl)methylen]cyclohexa-2,5-dien-1-one (1) transforms into a stable neutral open-shell species (1) via chemisorption on the Ag(111) surface. X-ray photoelectron spectroscopy reveals that the >C=O group of 1 reacts with the surface, forming a C-O-Ag linkage that induces an electronic rearrangement that transforms 1 to 1. We further show that surface reactivity is an important factor in this process whereby Au(111) is inert towards 1, whereas the Cu(111) surface leads to dehalogenation reactions. The radical nature of the Ag(111)-bound monolayer was further confirmed by angle-resolved photoelectron spectroscopy and electronic structure calculations, which provide evidence of the emergence of the singly occupied molecular orbital (SOMO) of 1. © 2020 American Chemical Society.

  • Neutron Activated 153Sm Sealed in Carbon Nanocapsules for in Vivo Imaging and Tumor Radiotherapy

    Wang J.T.-W., Klippstein R., Martincic M., Pach E., Feldman R., Šefl M., Michel Y., Asker D., Sosabowski J.K., Kalbac M., Da Ros T., Ménard-Moyon C., Bianco A., Kyriakou I., Emfietzoglou D., Saccavini J.-C., Ballesteros B., Al-Jamal K.T., Tobias G. ACS Nano; 14 (1): 129 - 141. 2020. 10.1021/acsnano.9b04898. IF: 13.903

    Electron Microscopy Unit

    Radiation therapy along with chemotherapy and surgery remain the main cancer treatments. Radiotherapy can be applied to patients externally (external beam radiotherapy) or internally (brachytherapy and radioisotope therapy). Previously, nanoencapsulation of radioactive crystals within carbon nanotubes, followed by end-closing, resulted in the formation of nanocapsules that allowed ultrasensitive imaging in healthy mice. Herein we report on the preparation of nanocapsules initially sealing "cold" isotopically enriched samarium (152Sm), which can then be activated on demand to their "hot" radioactive form (153Sm) by neutron irradiation. The use of "cold" isotopes avoids the need for radioactive facilities during the preparation of the nanocapsules, reduces radiation exposure to personnel, prevents the generation of nuclear waste, and evades the time constraints imposed by the decay of radionuclides. A very high specific radioactivity is achieved by neutron irradiation (up to 11.37 GBq/mg), making the "hot" nanocapsules useful not only for in vivo imaging but also therapeutically effective against lung cancer metastases after intravenous injection. The high in vivo stability of the radioactive payload, selective toxicity to cancerous tissues, and the elegant preparation method offer a paradigm for application of nanomaterials in radiotherapy. Copyright © 2019 American Chemical Society.

  • Neutron-irradiated antibody-functionalised carbon nanocapsules for targeted cancer radiotherapy

    Wang J.T.-W., Spinato C., Klippstein R., Costa P.M., Martincic M., Pach E., Ruiz de Garibay A.P., Ménard-Moyon C., Feldman R., Michel Y., Šefl M., Kyriakou I., Emfietzoglou D., Saccavini J.-C., Ballesteros B., Tobias G., Bianco A., Al-Jamal K.T. Carbon; 162: 410 - 422. 2020. 10.1016/j.carbon.2020.02.060. IF: 7.466

    Electron Microscopy Unit

    Radiotherapy is a cancer treatment utilising high doses of ionizing radiation to destroy cancer cells. Our team has pioneered neutron activation of 152Sm, filled and sealed into single-walled (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), to create stable and high-dose radioactive carbon nanocapsules for cancer radiotherapy. In this work, MWCNTs filled with enriched 152SmCl3 (Sm@MWCNTs) were sealed and irradiated, followed by surface functionalisation with an epidermal growth factor receptor (EGFR)-targeting antibody. Characterisation of functionalised Sm@MWCNTs was carried out using thermogravimetric analysis, gel electrophoresis and transmission electron microscopy. The organ biodistribution of the radioactive functionalised 153Sm@MWCNTs and therapeutic efficacy were studied in an experimental melanoma lung metastatic tumour model in mice after intravenous injection. Quantitative biodistribution analyses showed high accumulation of 153Sm@MWCNT-Ab in lung. Significant tumour growth reduction was induced by both treatments of 153Sm@MWCNTs functionalised with or without the antibody after a single intravenous injection. Although EGFR targeting showed no improvement in therapeutic efficacy, reduced spleen toxicity and normal haematological profiles were obtained for both functionalised derivatives. The current study demonstrated the possibility of performing chemical functionalisation and antibody conjugation on radioactive nanocapsules post-irradiation for the preparation of targeted radiopharmaceuticals. © 2020 Elsevier Ltd

  • Nonlocal Spin Dynamics in the Crossover from Diffusive to Ballistic Transport

    Vila M., Garcia J.H., Cummings A.W., Power S.R., Groth C.W., Waintal X., Roche S. Physical Review Letters; 124 (19, 196602) 2020. 10.1103/PhysRevLett.124.196602. IF: 9.227

    Theoretical and Computational Nanoscience

    Improved fabrication techniques have enabled the possibility of ballistic transport and unprecedented spin manipulation in ultraclean graphene devices. Spin transport in graphene is typically probed in a nonlocal spin valve and is analyzed using spin diffusion theory, but this theory is not necessarily applicable when charge transport becomes ballistic or when the spin diffusion length is exceptionally long. Here, we study these regimes by performing quantum simulations of graphene nonlocal spin valves. We find that conventional spin diffusion theory fails to capture the crossover to the ballistic regime as well as the limit of long spin diffusion length. We show that the latter can be described by an extension of the current theoretical framework. Finally, by covering the whole range of spin dynamics, our study opens a new perspective to predict and scrutinize spin transport in graphene and other two-dimensional material-based ultraclean devices. © 2020 American Physical Society.

  • Optical nanogap antennas as plasmonic biosensors for the detection of miRNA biomarkers

    Portela A., Calvo-Lozano O., Estevez M., Medina Escuela A., Lechuga L.M. Journal of Materials Chemistry B; 8 (19): 4310 - 4317. 2020. 10.1039/d0tb00307g. IF: 5.047

    NanoBiosensors and Bioanalytical Applications

    Nanoplasmonic biosensors based on nanogap antenna structures usually demand complex and expensive fabrication processes in order to achieve a good performance and sensitive detection. We here report the fabrication of large-area nanoplasmonic sensor chips based on nanogap antennas by employing a customized, simple and low-cost colloidal lithography process. By precisely controlling the angle for tilted e-beam metal evaporation, an elliptical mask is produced, which defines the total length of the dipole antenna nanostructures while assuring that the plasmonic response is oriented in the same direction along the sensor chip. Large-area sensor chips of nanogap antennas formed by pairs of gold nanodisks separated by gaps with an average size of 11.6 ± 4.7 nm are obtained. The optical characterization of the nanogap antenna structures in an attenuated total reflection (ATR) configuration shows a bulk refractive index sensitivity of 422 nm per RIU, which is in agreement with FDTD numerical simulations. The biosensing potential of the cm2-sized nanostructured plasmonic sensor chips has been evaluated for the detection of miRNA-210, a relevant biomarker for lung cancer diagnosis, through a DNA/miRNA hybridization assay. A limit of detection (LOD) of 0.78 nM (5.1 ng mL-1) was achieved with no need of further amplification steps, demonstrating the high sensitivity of these plasmonic nanogap antennas for the direct and label-free detection of low molecular weight biomolecules such as miRNAs. © The Royal Society of Chemistry 2020.

  • Organic-based field effect transistors for protein detection fabricated by inkjet-printing

    Martínez-Domingo C., Conti S., de la Escosura-Muñiz A., Terés L., Merkoçi A., Ramon E. Organic Electronics; 84 (105794) 2020. 10.1016/j.orgel.2020.105794. IF: 3.495

    Nanobioelectronics and Biosensors

    Biosensors based on Organic Field-Effect Transistors (OFETs) have attracted increasing attention due to the possibility of rapid, label-free, and inexpensive detection. Among all the different possibilities, inkjet-printed top-gate organic Field Effect Transistors-Based Biosensors (BioFETs) using a polymeric gate insulator have been seldom reported. In this work, a systematic investigation in terms of topographical and electrical characterization was carried out in order to find the optimal fabrication process for obtaining a reliable polymer insulator. Previous studies have demonstrated that the best electrical performance arises from the use of the perfluoropolymer Cytop™[12,13,14]. Consequently, a simple immobilization protocol was used to ensure the proper attachment of a model biomolecule onto the Cytop's hydrophobic surface whilst keeping its remarkable insulating properties with gate current in the range of dozens of pico-amperes. The top-gate inkjet-printed BioFETs presented in this study operate at threshold voltages in the range of 1–2 V and show durability even when exposed to oxygen plasma, wet amine functionalization treatments, and aqueous media. As a preliminary application, the inkjet-printed top-gate BioFETs is used for monitoring an immunoreaction by measuring changes in the drain current, paving the way for further use of this device in the immunosensing field. © 2020 Elsevier B.V.

  • P-Type Ultrawide-Band-Gap Spinel ZnGa2O4: New Perspectives for Energy Electronics

    Chikoidze E., Sartel C., Madaci I., Mohamed H., Vilar C., Ballesteros B., Belarre F., Del Corro E., Vales-Castro P., Sauthier G., Li L., Jennings M., Sallet V., Dumont Y., Pérez-Tomás A. Crystal Growth and Design; 20 (4): 2535 - 2546. 2020. 10.1021/acs.cgd.9b01669. IF: 4.153

    Electron Microscopy Unit | Advanced Electronic Materials and Devices

    The family of spinel compounds is a large and important class of multifunctional materials of general formulation AB2X4 with many advanced applications in energy and optoelectronic areas such as fuel cells, batteries, catalysis, photonics, spintronics, and thermoelectricity. In this work, it is demonstrated that the ternary ultrawide-band-gap (∼5 eV) spinel zinc gallate (ZnGa2O4) arguably is the native p-type ternary oxide semiconductor with the largest Eg value (in comparison with the recently discovered binary p-type monoclinic β-Ga2O3 oxide). For nominally undoped ZnGa2O4 the high-temperature Hall effect hole concentration was determined to be as large as p = 2 × 1015 cm-3, while hole mobilities were found to be μh = 7-10 cm2/(V s) (in the 680-850 K temperature range). An acceptor-like small Fermi level was further corroborated by X-ray spectroscopy and by density functional theory calculations. Our findings, as an important step toward p-type doping, opens up further perspectives for ultrawide-band-gap bipolar spinel electronics and further promotes ultrawide-band-gap ternary oxides such as ZnGa2O4 to the forefront of the quest of the next generation of semiconductor materials for more efficient energy optoelectronics and power electronics. Copyright © 2020 American Chemical Society.

  • Pathway selection as a tool for crystal defect engineering: A case study with a functional coordination polymer

    Abrishamkar A., Suárez–García S., Sevim S., Sorrenti A., Pons R., Liu S.-X., Decurtins S., Aromí G., Aguilà D., Pané S., deMello A.J., Rotaru A., Ruiz–Molina D., Puigmartí-Luis J. Applied Materials Today; 20 (100632) 2020. 10.1016/j.apmt.2020.100632. IF: 8.013

    Nanostructured Functional Materials

    New synthetic routes capable of achieving defect engineering of functional crystals through well-controlled pathway selection will spark new breakthroughs and advances towards unprecedented and unique functional materials and devices. In nature, the interplay of chemical reactions with the diffusion of reagents in space and time is already used to favor such pathway selection and trigger the formation of materials with bespoke properties and functions, even when the material composition is preserved. Following this approach, herein we show that a controlled interplay of a coordination reaction with mass transport (i.e. the diffusion of reagents) is essential to favor the generation of charge imbalance defects (i.e. protonation defects) in a final crystal structure (thermodynamic product). We show that this synthetic pathway is achieved with the isolation of a kinetic product (i.e. a metastable state), which can be only accomplished when a controlled interplay of the reaction with mass transport is satisfied. Accounting for the relevance of controlling, tuning and understanding structure-properties correlations, we have studied the spin transition evolution of a well-defined spin-crossover complex as a model system. © 2020 Elsevier Ltd

  • Photocurrent spectroscopy of in-plane surface conductive diamond homostructures

    Simon P., Beck P., Rathi A., Stutzmann M., Garrido J.A. Physical Review B; 101 (20, 205306) 2020. 10.1103/PhysRevB.101.205306. IF: 3.736

    Advanced Electronic Materials and Devices

    Electrical breakdown at hydrogen/oxygen interfaces is limiting the use of nanoscaled diamond devices for the control of optically active defect centers. In this work electron transport across an oxygen-terminated potential barrier in a hydrogen-terminated surface conductive diamond is investigated. We analyze temperature-dependent current-voltage characteristics for different barrier widths and report on a reduced effective barrier height compared to theoretical expectations. This is ascribed to an inhomogeneous potential landscape, as observed by Kelvin probe and conductive force microscopy. Furthermore, we use photocurrent spectroscopy to discuss possible transport processes and identify a field dependent absorption feature. A defect state involved in transport across the barrier is proposed at the hydrogen-oxygen barrier approximately 1eV above the valence band maximum. The new understanding enabled by our work may help to overcome the current limitations of diamond surface electronics. © 2020 American Physical Society.

  • Photoflexoelectric effect in halide perovskites

    Shu L., Ke S., Fei L., Huang W., Wang Z., Gong J., Jiang X., Wang L., Li F., Lei S., Rao Z., Zhou Y., Zheng R.-K., Yao X., Wang Y., Stengel M., Catalan G. Nature Materials; 19 (6): 605 - 609. 2020. 10.1038/s41563-020-0659-y. IF: 38.887

    Oxide Nanophysics

    Harvesting environmental energy to generate electricity is a key scientific and technological endeavour of our time. Photovoltaic conversion and electromechanical transduction are two common energy-harvesting mechanisms based on, respectively, semiconducting junctions and piezoelectric insulators. However, the different material families on which these transduction phenomena are based complicate their integration into single devices. Here we demonstrate that halide perovskites, a family of highly efficient photovoltaic materials1–3, display a photoflexoelectric effect whereby, under a combination of illumination and oscillation driven by a piezoelectric actuator, they generate orders of magnitude higher flexoelectricity than in the dark. We also show that photoflexoelectricity is not exclusive to halides but a general property of semiconductors that potentially enables simultaneous electromechanical and photovoltaic transduction and harvesting in unison from multiple energy inputs. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.

  • Preclinical evaluation of antigen-specific nanotherapy based on phosphatidylserine-liposomes for type 1 diabetes

    Villalba A., Rodriguez-Fernandez S., Ampudia R.-M., Cano-Sarabia M., Perna-Barrull D., Bertran-Cobo C., Ehrenberg C., Maspoch D., Vives-Pi M. Artificial Cells, Nanomedicine and Biotechnology; 48 (1): 77 - 83. 2020. 10.1080/21691401.2019.1699812. IF: 4.462

    Supramolecular NanoChemistry and Materials

    Type 1 diabetes (T1D) is an autoimmune disease caused by the destruction of insulin-producing cells. Due to the ability of apoptotic cells clearance to induce tolerance, we previously generated liposomes rich in phophatidylserine (PS) –a feature of apoptotic cells– loaded with insulin peptides to mimic apoptotic beta-cells. PS-liposomes arrested autoimmunity in experimental T1D through the induction of tolerance. The aim of this study was to investigate the potential of several peptides from different T1D autoantigens encapsulated in (PS)-liposomes for T1D prevention and to assess its safety. T1D autoantigens (Insulin, C-peptide, GAD65 and IA2) were encapsulated in PS-liposomes. Liposomes were administered to the 'gold-standard' model for the study of autoimmune T1D, the Non-Obese Diabetic mouse, that spontaneously develop the disease. Safety and toxicity of liposomes were also determined. Only PS-liposomes encapsulating insulin peptides decrease T1D incidence in the Non-Obese Diabetic mouse model. Disease prevention correlates with a decrease in the severity of the autoimmune islet destruction driven by leukocytes. PS-liposomes neither showed toxic effect nor secondary complications. Among the here referred autoantigens, insulin peptides are the best candidates to be encapsulated in liposomes, like an artificial apoptotic cell, for the arrest of autoimmunity in T1D in a safe manner. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

  • Production and processing of graphene and related materials

    Backes C., Abdelkader A.M., Alonso C., Andrieux-Ledier A., Arenal R., Azpeitia J., Balakrishnan N., Banszerus L., Barjon J., Bartali R., Bellani S., Berger C., Berger R., Ortega M.M.B., Bernard C., Beton P.H., Beyer A., Bianco A., Bøggild P., Bonaccorso F., Barin G.B., Botas C., Bueno R.A., Carriazo D., Castellanos-Gomez A., Christian M., Ciesielski A., Ciuk T., Cole M.T., Coleman J., Coletti C., Crema L., Cun H., Dasler D., De Fazio D., Díez N., Drieschner S., Duesberg G.S., Fasel R., Feng X., Fina A., Forti S., Galiotis C., Garberoglio G., García J.M., Garrido J.A., Gibertini M., Gölzhäuser A., Gómez J., Greber T., Hauke F., Hemmi A., Hernandez-Rodriguez I., Hirsch A., Hodge S.A., Huttel Y., Jepsen P.U., Jimenez I., Kaiser U., Kaplas T., Kim H., Kis A., Papagelis K., Kostarelos K., Krajewska A., Lee K., Li C., Lipsanen H., Liscio A., Lohe M.R., Loiseau A., Lombardi L., López M.F., Martin O., Martín C., Martínez L., Martin-Gago J.A., Martínez J.I., Marzari N., Mayoral A., McManus J., Melucci M., Méndez J., Merino C., Merino P., Meyer A.P., Miniussi E., Miseikis V., Mishra N., Morandi V., Munuera C., Muñoz R., Nolan H., Ortolani L., Ott A.K., Palacio I., Palermo V., Parthenios J., Paste 2D Materials; 7 (2, 022001) 2020. 10.1088/2053-1583/ab1e0a. IF: 7.343

    Nanomedicine | Advanced Electronic Materials and Devices

    We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. Section I is devoted to 'bottom up' approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers 'top down' techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers' and modified Hummers' methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resourceconsuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown. © 2020 The Author(s).

  • Protein corona fingerprinting to differentiate sepsis from non-infectious systemic inflammation

    Papafilippou L., Claxton A., Dark P., Kostarelos K., Hadjidemetriou M. Nanoscale; 12 (18): 10240 - 10253. 2020. 10.1039/d0nr02788j. IF: 6.970


    Rapid and accurate diagnosis of sepsis remains clinically challenging. The lack of specific biomarkers that can differentiate sepsis from non-infectious systemic inflammatory diseases often leads to excessive antibiotic treatment. Novel diagnostic tests are urgently needed to rapidly and accurately diagnose sepsis and enable effective treatment. Despite investment in cutting-edge technologies available today, the discovery of disease-specific biomarkers in blood remains extremely difficult. The highly dynamic environment of plasma restricts access to vital diagnostic information that can be obtained by proteomic analysis. Here, we employed clinically used lipid-based nanoparticles (AmBisome®) as an enrichment platform to analyze the human plasma proteome in the setting of sepsis. We exploited the spontaneous interaction of plasma proteins with nanoparticles (NPs) once in contact, called the 'protein corona', to discover previously unknown disease-specific biomarkers for sepsis diagnosis. Plasma samples obtained from non-infectious acute systemic inflammation controls and sepsis patients were incubated ex vivo with AmBisome® liposomes, and the resultant protein coronas were thoroughly characterised and compared by mass spectrometry (MS)-based proteomics. Our results demonstrate that the proposed nanoparticle enrichment technology enabled the discovery of 67 potential biomarker proteins that could reproducibly differentiate non-infectious acute systemic inflammation from sepsis. This study provides proof-of-concept evidence that nanoscale-based 'omics' enrichment technologies have the potential to substantially improve plasma proteomics analysis and to uncover novel biomarkers in a challenging clinical setting.

  • Quantitative theory of triplet pairing in the unconventional superconductor LaNiGa2

    Ghosh S.K., Csire G., Whittlesea P., Annett J.F., Gradhand M., Újfalussy B., Quintanilla J. Physical Review B; 101 (10, 100506) 2020. 10.1103/PhysRevB.101.100506. IF: 3.736

    Theory and Simulation

    The exceptionally low-symmetry crystal structures of the time-reversal symmetry-breaking superconductors LaNiC2 and LaNiGa2 lead to an internally antisymmetric nonunitary triplet state as the only possibility compatible with experiments. We argue that this state has a distinct signature: A double-peak structure in the density of states (DOS) which resolves in the spin channel in a particular way. We construct a detailed model of LaNiGa2 capturing its electronic band structure and magnetic properties ab initio. The pairing mechanism is described via a single adjustable parameter. The latter is fixed by the critical temperature Tc allowing parameter-free predictions. We compute the electronic specific heat and find excellent agreement with experiment. The size of the ordered moment in the superconducting state is compatible with zero-field muon spin relaxation experiments and the predicted spin-resolved DOS suggests the spin splitting is within the reach of present experimental technology. © 2020 American Physical Society.

  • Real-time Optical Dimensional Metrology via Diffractometry for Nanofabrication

    Whitworth G.L., Francone A., Sotomayor-Torres C.M., Kehagias N. Scientific Reports; 10 (1, 5371) 2020. 10.1038/s41598-020-61975-3. IF: 4.011

    Phononic and Photonic Nanostructures

    Surface patterning technologies represent a worldwide growing industry, creating smart surfaces and micro/nanoscale device. The advent of large-area, high-speed imprinting technologies has created an ever-growing need for rapid and non-destructive dimensional metrology techniques to keep pace with the speed of production. Here we present a new real-time optical scatterometry technique, applicable at the mesoscale when optical inspection produces multiple orders of diffraction. We validate this method by inspecting multiple silicon gratings with a variety of structural parameters. These measurements are cross-referenced with FIB, SEM and scanning stylus profilometry. Finally, we measure thermally imprinted structures as a function of imprinting temperature in order to demonstrate the method suitable for in-line quality control in nanoimprint lithography. © 2020, The Author(s).

  • Recent advances in fiber-shaped and planar-shaped textile solar cells

    Hatamvand M., Kamrani E., Lira-Cantú M., Madsen M., Patil B.R., Vivo P., Mehmood M.S., Numan A., Ahmed I., Zhan Y. Nano Energy; 71 (104609) 2020. 10.1016/j.nanoen.2020.104609. IF: 15.548

    Nanostructured Materials for Photovoltaic Energy

    During the last few years, textile solar cells with planar and fiber-shaped configurations have attracted enormous research interest. These flexible-type solar cells have a huge potential applicability in self-powered and battery-less electronics, which will impact many sectors, and particularly the Internet of Things. Textile solar cells are lightweight, super-flexible, formable, and foldable. Thus, they could be ideal power-harvester alternatives to common flexible solar cells required in smart textiles, electronic textiles, and wearable electronic devices. This review presents a brief overview on fiber-shaped and planar-shaped solar cells, and it introduces the most recent research reports on the different types of textile solar cells, including details on their fabrication techniques. It also addresses the current challenges and limitations of their technology development, and the encountered issues for their future application and integration in novel devices. © 2020 Elsevier Ltd

  • Revealing Strain Effects on the Chemical Composition of Perovskite Oxide Thin Films Surface, Bulk, and Interfaces

    van den Bosch C.A.M., Cavallaro A., Moreno R., Cibin G., Kerherve G., Caicedo J.M., Lippert T.K., Doebeli M., Santiso J., Skinner S.J., Aguadero A. Advanced Materials Interfaces; 7 (2, 1901440) 2020. 10.1002/admi.201901440. IF: 4.713

    Nanomaterials Growth Unit

    Understanding the effects of lattice strain on oxygen surface and diffusion kinetics in oxides is a controversial subject that is critical for developing efficient energy storage and conversion materials. In this work, high-quality epitaxial thin films of the model perovskite La0.5Sr0.5Mn0.5Co0.5O3− δ (LSMC), under compressive or tensile strain, are characterized with a combination of in situ and ex situ bulk and surface-sensitive techniques. The results demonstrate a nonlinear correlation of mechanical and chemical properties as a function of the operation conditions. It is observed that the effect of strain on reducibility is dependent on the “effective strain” induced on the chemical bonds. In-plain strain, and in particular the relative BO length bond, is the key factor controlling which of the B-site cation can be reduced preferentially. Furthermore, the need to use a set of complimentary techniques to isolate different chemically induced strain effects is proven. With this, it is confirmed that tensile strain favors the stabilization of a more reduced lattice, accompanied by greater segregation of strontium secondary phases and a decrease of oxygen exchange kinetics on LSMC thin films. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Rhodium as efficient additive for boosting acetone sensing by TiO2 nanocrystals. Beyond the classical view of noble metal additives

    Epifani M., Kaciulis S., Mezzi A., Zhang T., Arbiol J., Siciliano P., Landström A., Concina I., Moumen A., Comini E., Xiangfeng C. Sensors and Actuators, B: Chemical; 319 (128338) 2020. 10.1016/j.snb.2020.128338. IF: 6.393

    Advanced Electron Nanoscopy

    Anatase TiO2 nanocrystals were prepared by solvothermal synthesis and modified by in- situ generated Rh nanoparticles, with a starting nominal Rh:Ti atomic concentration of 0.01 and 0.05. After heat-treatment at 400 °C the TiO2 host was still in the anatase crystallographic phase, embedding Rh nanoparticles homogeneously distributed and whose surface had been oxidized to Rh2O3, as established by X-ray diffraction, Transmission Electron Microscopy and X-ray Photoelectron spectroscopy. Moreover, Rh seemed also homogeneously distributed in elemental form or as Rh2O3 nanoclusters. The acetone sensing properties of the resulting materials were enhanced by Rh addition, featuring a response increase of one order of magnitude at the best operating temperature of 300 °C. Moreover, Rh addition enlarged the detection range down to 10 ppm whereas pure TiO2 was not able of giving an appreciable response already at a concentration as high as 50 ppm. From the sensing data, the enhancement of the sensor response was attributed to the finely dispersed Rh species and not to the oxidized Rh nanocrystals. © 2020 Elsevier B.V.

  • Selective stamping of laser scribed rGO nanofilms: From sensing to multiple applications

    Giacomelli C., Álvarez-Diduk R., Testolin A., Merkoçi A. 2D Materials; 7 (2, 024006) 2020. 10.1088/2053-1583/ab68a7. IF: 7.343

    Nanobioelectronics and Biosensors

    A rapid low-cost technology to produce highly conductive laser-scribed reduced-graphene oxide (rGO) thin films on flexible substrates is developed. Isolated rGO films, up to 30 nm thick and with a conductivity of 102 S m-1 are produced at room temperature in a three-step process: filtering the graphene oxide (GO) solution through nitrocellulose membranes, reduction of GO surface using a DVD-burner laser and solvent-free transfer of the resulting rGO pattern onto new substrates via pressure-based mechanism. The loss of density in the reduced part produces an increase in the thickness enabling the transfer of rGO only. The rGO is characterized with several analytical techniques, and its reduction degree, thickness, morphology, electrochemical and electromechanical properties are investigated and optimized. The validation of the technology is tested using a wide variety of substrates, and its applicability as a sensing platform for dopamine detection and back electrode in an electroluminescent lamp is demonstrated, opening the venue for a plethora of other new applications. © 2020 IOP Publishing Ltd.

  • Semiconductor-Ferromagnetic Insulator-Superconductor Nanowires: Stray Field and Exchange Field

    Liu Y., Vaitiekėnas S., Martí-Sánchez S., Koch C., Hart S., Cui Z., Kanne T., Khan S.A., Tanta R., Upadhyay S., Cachaza M.E., Marcus C.M., Arbiol J., Moler K.A., Krogstrup P. Nano Letters; 20 (1): 456 - 462. 2020. 10.1021/acs.nanolett.9b04187. IF: 12.279

    Advanced Electron Nanoscopy

    Nanowires can serve as flexible substrates for hybrid epitaxial growth on selected facets, allowing for the design of heterostructures with complex material combinations and geometries. In this work we report on hybrid epitaxy of freestanding vapor-liquid-solid grown and in-plane selective area grown semiconductor-ferromagnetic insulator-superconductor (InAs/EuS/Al) nanowire heterostructures. We study the crystal growth and complex epitaxial matching of wurtzite and zinc-blende InAs/rock-salt EuS interfaces as well as rock-salt EuS/face-centered cubic Al interfaces. Because of the magnetic anisotropy originating from the nanowire shape, the magnetic structure of the EuS phase is easily tuned into single magnetic domains. This effect efficiently ejects the stray field lines along the nanowires. With tunnel spectroscopy measurements of the density of states, we show that the material has a hard induced superconducting gap, and magnetic hysteretic evolution which indicates that the magnetic exchange fields are not negligible. These hybrid nanowires fulfill key material requirements for serving as a platform for spin-based quantum applications, such as scalable topological quantum computing. Copyright © 2019 American Chemical Society.

  • Siesta: Recent developments and applications

    García A., Papior N., Akhtar A., Artacho E., Blum V., Bosoni E., Brandimarte P., Brandbyge M., Cerdá J.I., Corsetti F., Cuadrado R., Dikan V., Ferrer J., Gale J., García-Fernández P., García-Suárez V.M., García S., Huhs G., Illera S., Korytár R., Koval P., Lebedeva I., Lin L., López-Tarifa P., Mayo S.G., Mohr S., Ordejón P., Postnikov A., Pouillon Y., Pruneda M., Robles R., Sánchez-Portal D., Soler J.M., Ullah R., Yu V.W.-Z., Junquera J. The Journal of chemical physics; 152 (20): 204108. 2020. 10.1063/5.0005077. IF: 2.997

    Theory and Simulation

    A review of the present status, recent enhancements, and applicability of the Siesta program is presented. Since its debut in the mid-1990s, Siesta's flexibility, efficiency, and free distribution have given advanced materials simulation capabilities to many groups worldwide. The core methodological scheme of Siesta combines finite-support pseudo-atomic orbitals as basis sets, norm-conserving pseudopotentials, and a real-space grid for the representation of charge density and potentials and the computation of their associated matrix elements. Here, we describe the more recent implementations on top of that core scheme, which include full spin-orbit interaction, non-repeated and multiple-contact ballistic electron transport, density functional theory (DFT)+U and hybrid functionals, time-dependent DFT, novel reduced-scaling solvers, density-functional perturbation theory, efficient van der Waals non-local density functionals, and enhanced molecular-dynamics options. In addition, a substantial effort has been made in enhancing interoperability and interfacing with other codes and utilities, such as wannier90 and the second-principles modeling it can be used for, an AiiDA plugin for workflow automatization, interface to Lua for steering Siesta runs, and various post-processing utilities. Siesta has also been engaged in the Electronic Structure Library effort from its inception, which has allowed the sharing of various low-level libraries, as well as data standards and support for them, particularly the PSeudopotential Markup Language definition and library for transferable pseudopotentials, and the interface to the ELectronic Structure Infrastructure library of solvers. Code sharing is made easier by the new open-source licensing model of the program. This review also presents examples of application of the capabilities of the code, as well as a view of on-going and future developments.

  • Size-Dependent Pulmonary Impact of Thin Graphene Oxide Sheets in Mice: Toward Safe-by-Design

    Rodrigues A.F., Newman L., Jasim D., Mukherjee S.P., Wang J., Vacchi I.A., Ménard-Moyon C., Bianco A., Fadeel B., Kostarelos K., Bussy C. Advanced Science; 2020. 10.1002/advs.201903200. IF: 15.804


    Safety assessment of graphene-based materials (GBMs) including graphene oxide (GO) is essential for their safe use across many sectors of society. In particular, the link between specific material properties and biological effects needs to be further elucidated. Here, the effects of lateral dimensions of GO sheets in acute and chronic pulmonary responses after single intranasal instillation in mice are compared. Micrometer-sized GO induces stronger pulmonary inflammation than nanometer-sized GO, despite reduced translocation to the lungs. Genome-wide RNA sequencing also reveals distinct size-dependent effects of GO, in agreement with the histopathological results. Although large GO, but not the smallest GO, triggers the formation of granulomas that persists for up to 90 days, no pulmonary fibrosis is observed. These latter results can be partly explained by Raman imaging, which evidences the progressive biotransformation of GO into less graphitic structures. The findings demonstrate that lateral dimensions play a fundamental role in the pulmonary response to GO, and suggest that airborne exposure to micrometer-sized GO should be avoided in the production plant or applications, where aerosolized dispersions are likely to occur. These results are important toward the implementation of a safer-by-design approach for GBM products and applications, for the benefit of workers and end-users. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Stability of Pd3Pb Nanocubes during Electrocatalytic Ethanol Oxidation

    Yu X., Luo Z., Zhang T., Tang P., Li J., Wang X., Llorca J., Arbiol J., Liu J., Cabot A. Chemistry of Materials; 32 (5): 2044 - 2052. 2020. 10.1021/acs.chemmater.9b05094. IF: 10.159

    Advanced Electron Nanoscopy

    Intermetallic Pd3Pb nanocrystals with controlled size and cubic geometry exposing (100) facets are synthesized and tested as electrocatalysts for ethanol oxidation in alkaline media. We observe the ethanol oxidation activity and stability to be size-dependent. The 10 nm Pd3Pb nanocrystals display the highest initial current densities, but after few hundred cycles, the current density of smaller nanocrystals becomes much larger. All of the catalysts exhibit a pronounced current decay during the first 500 s of continuous operation, which is associated with the accumulation of strongly adsorbed reaction intermediates, blocking reaction sites. These adsorbed species can be removed by cycling the catalysts or maintaining them at slightly higher potentials for a short period of time to oxidize and later reduce the Pd surface. Such simple cleaning processes, that can be performed during operation breaks without cell disassembly, is sufficient to effectively remove the poisoning species adsorbed on the surface and recover the electrocatalytic activity. Copyright © 2020 American Chemical Society.

  • Strain-Engineered Ferroelastic Structures in PbTiO3 Films and Their Control by Electric Fields

    Langenberg E., Paik H., Smith E.H., Nair H.P., Hanke I., Ganschow S., Catalan G., Domingo N., Schlom D.G. ACS Applied Materials and Interfaces; 12 (18): 20691 - 20703. 2020. 10.1021/acsami.0c04381. IF: 8.456

    Oxide Nanophysics

    We study the interplay between epitaxial strain, film thickness, and electric field in the creation, modification, and design of distinct ferroelastic structures in PbTiO3 thin films. Strain and thickness greatly affect the structures formed, providing a two-variable parameterization of the resulting self-assembly. Under applied electric fields, these strain-engineered ferroelastic structures are highly malleable, especially when a/c and a1/a2 superdomains coexist. To reconfigure the ferroelastic structures and achieve self-assembled nanoscale-ordered morphologies, pure ferroelectric switching of individual c-domains within the a/c superdomains is essential. The stability, however, of the electrically written ferroelastic structures is in most cases ephemeral; the speed of the relaxation process depends sensitively on strain and thickness. Only under low tensile strain - as is the case for PbTiO3 on GdScO3 - and below a critical thickness do the electrically created a/c superdomain structures become stable for days or longer, making them relevant for reconfigurable nanoscale electronics or nonvolatile electromechanical applications. Copyright © 2020 American Chemical Society.

  • Supergiant Barocaloric Effects in Acetoxy Silicone Rubber over a Wide Temperature Range: Great Potential for Solid-state Cooling

    Imamura W., Usuda É.O., Paixão L.S., Bom N.M., Gomes A.M., Carvalho A.M.G. Chinese Journal of Polymer Science (English Edition); 2020. 10.1007/s10118-020-2423-9.

    Solid-state cooling based on caloric effects is considered a viable alternative to replace the conventional vapor-compression refrigeration systems. Regarding barocaloric materials, recent results show that elastomers are promising candidates for cooling applications around room-temperature. In the present paper, we report supergiant barocaloric effects observed in acetoxy silicone rubber—a very popular, low-cost and environmentally friendly elastomer. Huge values of adiabatic temperature change and reversible isothermal entropy change were obtained upon moderate applied pressures and relatively low strains. These huge barocaloric changes are associated both to the polymer chain rearrangements induced by confined compression and to the first-order structural transition. The results are comparable to the best barocaloric materials reported so far, opening encouraging prospects for the application of elastomers in near future solid-state cooling devices. © 2020, Chinese Chemical Society Institute of Chemistry, Chinese Academy of Sciences Springer-Verlag GmbH Germany, part of Springer Nature.

  • Supertetragonal Phases of Perovskite Oxides: Insights from Electronic Structure Calculations

    Cohen N., Diéguez O. Israel Journal of Chemistry; 2020. 10.1002/ijch.201900135. IF: 2.220

    Theory and Simulation

    We review some of the insights that electronic-structure calculations has brought about the properties of the materials with the largest electric polarization known – supertetragonal perovskite oxides. These are materials whose structure corresponds to a perovskite that has been substantially strechted along one of its pseudocubic axes. They grow in different forms: bulk crystals (such as BiCoO3), epitaxial films (such as BiFeO3), nanowires whose inside is under negative pressure (such as PbTiO3), and others. Electronic structure calculations based on density-functional theory have revealed that supertetragonality potentially exist for many perovskite oxides under the right conditions, and they have helped explain why some of those conditions are easy to reach for some of the materials of the family, but not for others. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Supramolecular Fullerene Sponges as Catalytic Masks for Regioselective Functionalization of C60

    Fuertes-Espinosa C., García-Simón C., Pujals M., Garcia-Borràs M., Gómez L., Parella T., Juanhuix J., Imaz I., Maspoch D., Costas M., Ribas X. Chem; 6 (1): 169 - 186. 2020. 10.1016/j.chempr.2019.10.010. IF: 18.205

    Supramolecular NanoChemistry and Materials

    Isomer-pure poly-functionalized fullerenes are required to boost the development of fullerene chemistry in all fields. On a general basis, multi-adduct mixtures with uncontrolled regioselectivity are obtained, and the use of chromatographic purification is prohibitively costly and time consuming, especially in the production of solar cells. Single-isomer poly-functionalized fullerenes are only accessible via stoichiometric, multistep paths entailing protecting-unprotecting sequences. Herein, a nanocapsule is used as a supramolecular tetragonal prismatic mask to exert full control on the reactivity and the equatorial regioselectivity of Bingel-Hirsch cyclopropanation reactions of a confined C60 guest. Thus, equatorial bis-, tris-, and tetrakis-C60 homo-adducts are exclusively obtained in a stepwise manner. Furthermore, isomer-pure equatorial hetero-tetrakis-adducts or hetero-Th-hexakis-adducts are synthesized at will in one-pot synthesis for the first time. This work provides a synthetically valuable path to produce a plethora of new pure-isomer poly-functionalized C60-based compounds as candidates for testing in solar cell devices and biomedical applications. Video Abstract: The supramolecular mask protocol is a significant step forward for the regioselective functionalization of fullerenes. The exquisite ability to form pure-isomer poly-functionalized C60 adducts, overcoming tedious and non-practical chromatographic separations, allows for their direct testing in solar cell prototypes. Furthermore, the supramolecular mask strategy can be applied to C70 or higher fullerenes, opening a plethora of poly-functionalized fullerene derivatives to be synthesized and tested. Moreover, apart from the nucleophilic cyclopropanations reported herein, the protocol is currently being expanded to Diels-Alder (DA), 1,3-dipolar cycloadditions and PC60BM-type cyclopropanations, thus enabling a variety of regioselective functionalization reactions. This supramolecular mask strategy can help the discovery of the next generation of improved solar cells (organic or perovskite based) or new drug candidates. An unprecedented and straightforward supramolecular mask strategy to prepare exclusively equatorial bis-, tris-, and tetrakis-cyclopropanated-C60 Bingel-Hirsch derivatives is reported. By taking advantage of the high affinity for fullerene of tetragonal prismatic supramolecular cages, a highly stable C60⊂1a·(BArF)8 host-guest complex is submitted to Bingel-Hirsch cyclopropanation reaction conditions. Regioselectivity is strictly dictated by the four cross-shaped apertures of the nanocapsule in a controlled fashion. Moreover, stepwise-cyclopropanated adducts up to tetrakis additions are obtained in excellent yields and purities. © 2019 Elsevier Inc.

  • Switchless multiplexing of graphene active sensor arrays for brain mapping

    Garcia-Cortadella R., Schäfer N., Cisneros-Fernandez J., Ré L., Illa X., Schwesig G., Moya A., Santiago S., Guirado G., Villa R., Sirota A., Serra-Graells F., Garrido J.A., Guimerà-Brunet A. Nano Letters; 20 (5): 3528 - 3537. 2020. 10.1021/acs.nanolett.0c00467. IF: 12.279

    Advanced Electronic Materials and Devices

    Sensor arrays used to detect electrophysiological signals from the brain are paramount in neuroscience. However, the number of sensors that can be interfaced with macroscopic data acquisition systems currently limits their bandwidth. This bottleneck originates in the fact that, typically, sensors are addressed individually, requiring a connection for each of them. Herein, we present the concept of frequency-division multiplexing (FDM) of neural signals by graphene sensors. We demonstrate the high performance of graphene transistors as mixers to perform amplitude modulation (AM) of neural signals in situ, which is used to transmit multiple signals through a shared metal line. This technology eliminates the need for switches, remarkably simplifying the technical complexity of state-of-the-art multiplexed neural probes. Besides, the scalability of FDM graphene neural probes has been thoroughly evaluated and their sensitivity demonstrated in vivo. Using this technology, we envision a new generation of high-count conformal neural probes for high bandwidth brain machine interfaces. © 2020 American Chemical Society.

  • Synergistic computational-experimental discovery of highly selective ptcu nanocluster catalysts for acetylene semihydrogenation

    Ayodele O.B., Cai R., Wang J., Ziouani Y., Liang Z., Spadaro M.C., Kovnir K., Arbiol J., Akola J., Palmer R.E., Kolen'ko Y.V. ACS Catalysis; 10 (1): 451 - 457. 2020. 10.1021/acscatal.9b03539. IF: 12.221

    Advanced Electron Nanoscopy

    Semihydrogenation of acetylene (SHA) in an ethylene-rich stream is an important process for polymer industries. Presently, Pd-based catalysts have demonstrated good acetylene conversion (XC2H2), however, at the expense of ethylene selectivity (SC2H4). In this study, we have employed a systematic approach using density functional theory (DFT) to identify the best catalyst in a Cu-Pt system. The DFT results showed that with a 55 atom system at∼1.1 Pt/Cu ratio for Pt28Cu27/Al2O3, the d-band center shifted -2.2 eV relative to the Fermi level leading to electron-saturated Pt, which allows only adsorption of ethylene via a π -bond, resulting in theoretical 99.7% SC2H4 at nearly complete XC2H2. Based on the DFT results, Pt-Cu/Al2O3 (PtCu) and Pt/Al2O3 (Pt) nanocatalysts were synthesized via cluster beam deposition (CBD), and their properties and activities were correlated with the computational predictions. For bimetallic PtCu, the electron microscopy results show the formation of alloys. The bimetallic PtCu catalyst closely mimics the DFT predictions in terms of both electronic structure, as confirmed by X-ray photoelectron spectroscopy, and catalytic activity. The alloying of Pt with Cu was responsible for the high C2H4 specific yield resulting from electron transfer between Cu and Pt, thus making PtCu a promising catalyst for SHA. © 2019 American Chemical Society.

  • Temperature-independent giant dielectric response in transitional BaTiO3 thin films

    Everhardt A.S., Denneulin T., Grünebohm A., Shao Y.-T., Ondrejkovic P., Zhou S., Domingo N., Catalan G., Hlinka J., Zuo J.-M., Matzen S., Noheda B. Applied Physics Reviews; 7 (1, 011402) 2020. 10.1063/1.5122954. IF: 12.750

    Oxide Nanophysics

    Ferroelectric materials exhibit the largest dielectric permittivities and piezoelectric responses in nature, making them invaluable in applications from supercapacitors or sensors to actuators or electromechanical transducers. The origin of this behavior is their proximity to phase transitions. However, the largest possible responses are most often not utilized due to the impracticality of using temperature as a control parameter and to operate at phase transitions. This has motivated the design of solid solutions with morphotropic phase boundaries between different polar phases that are tuned by composition and that are weakly dependent on temperature. Thus far, the best piezoelectrics have been achieved in materials with intermediate (bridging or adaptive) phases. But so far, complex chemistry or an intricate microstructure has been required to achieve temperature-independent phase-transition boundaries. Here, we report such a temperature-independent bridging state in thin films of chemically simple BaTiO3. A coexistence among tetragonal, orthorhombic, and their bridging low-symmetry phases are shown to induce continuous vertical polarization rotation, which recreates a smear in-transition state and leads to a giant temperature-independent dielectric response. The current material contains a ferroelectric state that is distinct from those at morphotropic phase boundaries and cannot be considered as ferroelectric crystals. We believe that other materials can be engineered in a similar way to contain a ferroelectric state with gradual change of structure, forming a class of transitional ferroelectrics. Similar mechanisms could be utilized in other materials to design low-power ferroelectrics, piezoelectrics, dielectrics, or shape-memory alloys, as well as efficient electro- and magnetocalorics. © 2020 Author(s).

  • Terahertz Nonlinear Optics of Graphene: From Saturable Absorption to High-Harmonics Generation

    Hafez H.A., Kovalev S., Tielrooij K.-J., Bonn M., Gensch M., Turchinovich D. Advanced Optical Materials; 8 (3, 1900771) 2020. 10.1002/adom.201900771. IF: 7.125

    Ultrafast Dynamics in Nanoscale Systems

    Graphene has long been predicted to show exceptional nonlinear optical properties, especially in the technologically important terahertz (THz) frequency range. Recent experiments have shown that this atomically thin material indeed exhibits possibly the largest nonlinear coefficients of any material known to date, paving the way for practical graphene-based applications in ultrafast (opto-)electronics operating at THz rates. Here the advances in the booming field of nonlinear THz optics of graphene are reported, and the state-of-the-art understanding of the nature of the nonlinear interaction of graphene with the THz fields based on the thermodynamic model of electron transport in graphene is described. A comparison between different mechanisms of nonlinear interaction of graphene with light fields in THz, infrared, and visible frequency ranges is also provided. Finally, the perspectives for the expected technological applications of graphene based on its extraordinary THz nonlinear properties are summarized. This report covers the evolution of the field of THz nonlinear optics of graphene from the very pioneering to the state-of-the-art works. It also serves as a concise overview of the current understanding of THz nonlinear optics of graphene and as a compact reference for researchers entering the field, as well as for the technology developers. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • The formation of oriented barium carbonate from the decomposition of yttria-doped barium zirconate films

    Jennings D., Ricote S., Santiso J., Reimanis I. Scripta Materialia; 186: 401 - 405. 2020. 10.1016/j.scriptamat.2020.05.028. IF: 4.539

    Nanomaterials Growth Unit

    Yttria doped barium zirconate (BZY) thin films show promise thanks to their high proton conductivities and their possibility for use in studying fundamental processes such as exsolution. This work demonstrates that highly oriented BZY thin (45 nm) films on (100) single crystal strontium titanate decompose into oriented barium carbonate rods and yttria stabilized zirconia when exposed to industrial grade Ar or pure CO2 at 800 °C. It is shown with transmission electron microscopy that the rods nucleate on the BZY surface. The causes and modes of decomposition in these thin films are discussed in detail. © 2020 Acta Materialia Inc.

  • Therapeutic potential of nicotinamide adenine dinucleotide (NAD)

    Arenas-Jal M., Suñé-Negre J.M., García-Montoya E. European Journal of Pharmacology; 879 (173158) 2020. 10.1016/j.ejphar.2020.173158. IF: 3.170

    Supramolecular NanoChemistry and Materials

    Nicotinamide adenine nucleotide (NAD) is a small ubiquitous hydrophilic cofactor that participates in several aspects of cellular metabolism. As a coenzyme it has an essential role in the regulation of energetic metabolism, but it is also a cosubstrate for enzymes that regulate fundamental biological processes such as transcriptional regulation, signaling and DNA repairing among others. The fluctuation and oxidative state of NAD levels regulate the activity of these enzymes, which is translated into marked effects on cellular function. While alterations in NAD homeostasis are a common feature of different conditions and age-associated diseases, in general, increased NAD levels have been associated with beneficial health effects. Due to its therapeutic potential, the interest in this molecule has been renewed, and the regulation of NAD metabolism has become an attractive target for drug discovery. In fact, different approaches to replenish or increase NAD levels have been tested, including enhancement of biosynthesis and inhibition of NAD breakdown. Despite further research is needed, this review provides an overview and update on NAD metabolism, including the therapeutic potential of its regulation, as well as pharmacokinetics, safety, precautions and formulation challenges of NAD supplementation. © 2020 Elsevier B.V.

  • Tunable room-temperature spin galvanic and spin Hall effects in van der Waals heterostructures

    Benítez L.A., Savero Torres W., Sierra J.F., Timmermans M., Garcia J.H., Roche S., Costache M.V., Valenzuela S.O. Nature Materials; 19 (2): 170 - 175. 2020. 10.1038/s41563-019-0575-1. IF: 38.887

    Theoretical and Computational Nanoscience | Physics and Engineering of Nanodevices

    Spin–orbit coupling stands as a powerful tool to interconvert charge and spin currents and to manipulate the magnetization of magnetic materials through spin-torque phenomena. However, despite the diversity of existing bulk materials and the recent advent of interfacial and low-dimensional effects, control of this interconversion at room temperature remains elusive. Here, we demonstrate strongly enhanced room-temperature spin-to-charge interconversion in graphene driven by the proximity of WS2. By performing spin precession experiments in appropriately designed Hall bars, we separate the contributions of the spin Hall and the spin galvanic effects. Remarkably, their corresponding conversion efficiencies can be tailored by electrostatic gating in magnitude and sign, peaking near the charge neutrality point with an equivalent magnitude that is comparable to the largest efficiencies reported to date. Such electric-field tunability provides a building block for spin generation free from magnetic materials and for ultra-compact magnetic memory technologies. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.

  • Ultrathin Films of Porous Metal–Organic Polyhedra for Gas Separation

    Andrés M.A., Carné-Sánchez A., Sánchez-Laínez J., Roubeau O., Coronas J., Maspoch D., Gascón I. Chemistry - A European Journal; 26 (1): 143 - 147. 2020. 10.1002/chem.201904141. IF: 5.160

    Supramolecular NanoChemistry and Materials

    Ultrathin films of a robust RhII-based porous metal–organic polyhedra (MOP) have been obtained. Homogeneous and compact monolayer films (ca. 2.5 nm thick) were first formed at the air–water interface, deposited onto different substrates and characterized using spectroscopic methods, scanning transmission electron microscopy and atomic force microscopy. As a proof of concept, the gas separation performance of MOP-supported membranes has also been evaluated. Selective MOP ultrathin films (thickness ca. 60 nm) exhibit remarkable CO2 permeance and CO2/N2 selectivity, demonstrating the great combined potential of MOP and Langmuir-based techniques in separation technologies. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Understanding galvanic replacement reactions: the case of Pt and Ag

    Merkoçi F., Patarroyo J., Russo L., Piella J., Genç A., Arbiol J., Bastús N.G., Puntes V. Materials Today Advances; 5 (100037) 2020. 10.1016/j.mtadv.2019.100037. IF: 0.000

    Inorganic Nanoparticles | Advanced Electron Nanoscopy

    Synthesis of nanocrystals (NCs), where material science elements are addressed with organic chemistry precision techniques, is especially challenging and difficult to control. This difficulty arises from the increased complexity of the mineralization processes and the generation of a liquid-solid interface. These aspects, along with a strong susceptibility to reaction kinetics, ultimately translate into serious challenges for reproducibility and morphological control. By systematically varying the different parameters used to control the morphology of NCs, including complexing agents, coreducers, and cooxidants, the general reaction landscape can be mapped and the most stable and reproducible recipes can be identified. We apply this concept to the model transmetallation reaction between immiscible Pt and Ag forming hollow Pt NCs by galvanic replacement reactions. In this work, 648 synthetic recipes were performed and characterized per duplicate, from which a subset of 307 recipes leading to the controlled formation of hollow NCs were further analyzed to correlate reaction conditions with the final obtained structure and stability (reproducibility). As a result, we present robust general synthetic protocols leading to the ad hoc production of Pt-based hollow NCs with independent control of shell thickness, void size, surface roughness, and degree of porosity. © 2019 The Authors

  • Unfolding method for periodic twisted systems with commensurate Moiré patterns

    Sánchez-Ochoa F., Hidalgo F., Pruneda M., Noguez C. Journal of Physics Condensed Matter; 32 (2, 025501) 2020. 10.1088/1361-648X/ab44f0. IF: 2.711

    Theory and Simulation

    We present a general unfolding method for the electronic bands of systems with double-periodicity. Within density functional theory with atomic orbitals as basis-set, our method takes into account two symmetry operations of the primitive cell: a standard expansion and a single rotation, letting to elucidate the physical effects associated to the mutual interactions between systems with more than one periodicity. As a result, our unfolding method allows studying the electronic properties of vertically stacked two-dimensional homo-or heterostructures. We apply our method to study 3 × 3single-layer graphene, √13×√ twisted single-layer graphene, and 2√3×2√3 graphene-√7×√7 tungsten disulfide heterostructure with an interlayer angle of 10.9°. Our unfolding method allows observing typical mini gaps reported in heterostructures, as well as other electronic deviations from pristine structures, impossible to distinguish without an unfolding method. We anticipate that this unfolding method can be useful to compare with experiments to elucidate the electronic properties of two-dimensional homo-or heterostructures, where the interlayer angle can be considered as an additional parameter. © 2019 IOP Publishing Ltd.

  • Waste Tire Rubber-based Refrigerants for Solid-state Cooling Devices

    Bom N.M., Usuda É.O., da Silva Gigliotti M., de Aguiar D.J.M., Imamura W., Paixão L.S., Carvalho A.M.G. Chinese Journal of Polymer Science (English Edition); 38 (7): 769 - 775. 2020. 10.1007/s10118-020-2385-y. IF: 2.804

    Atomic Manipulation and Spectroscopy

    Management of discarded tires is a compelling environmental issue worldwide. Although there are several approaches developed to recycle waste tire rubbers, their application in solid-state cooling is still unexplored. Considering the high barocaloric potential verified for elastomers, the use of waste tire rubber (WTR) as a refrigerant in solid-state cooling devices is very promising. Herein, we investigated the barocaloric effects in WTR and polymer blends made of vulcanized natural rubber (VNR) and WTR, to evaluate its feasibility for solid-state cooling technologies. The adiabatic temperature changes and the isothermal entropy changes reach giant values, as well as the performance parameters, being comparable or even better than most barocaloric materials in literature. Moreover, pure WTR and WTR-based samples also present a faster thermal exchange than VNR, consisting of an additional advantage of using these discarded materials. Thus, the present findings evidence the encouraging perspectives of employing waste rubbers in solid-state cooling based on barocaloric effects, contributing to both the recycling of polymers and the sustainable energy technology field. © 2020, Chinese Chemical Society Institute of Chemistry, Chinese Academy of Sciences Springer-Verlag GmbH Germany, part of Springer Nature.

  • Water/methanol solutions characterized by liquid μ-jet XPS and DFT—The methanol hydration case

    Pellegrin E., Perez-Dieste V., Escudero C., Rejmak P., Gonzalez N., Fontsere A., Prat J., Fraxedas J., Ferrer S. Journal of Molecular Liquids; 300 (112258) 2020. 10.1016/j.molliq.2019.112258. IF: 4.561

    Force Probe Microscopy and Surface Nanoengineering

    The advent of liquid μ-jet setups as proposed by Faubel and Winter – in conjunction with X-ray Photoemission Spectroscopy (XPS) – has opened up a large variety of experimental possibilities in the field of atomic and molecular physics. In this study, we present first results from a synchrotron-based XPS core level and valence band electron spectroscopy study on water (10-4 M aqueous NaCl solution) as well as a water/methanol mixture using the newly commissioned ALBA liquid μ-jet setup. The experimental results are compared with simulations from density functional theory (DFT) regarding the electronic structure of single molecules, pure molecular clusters, and mixed clusters configurations as well as previous experimental studies. We give a detailed interpretation of the core level and valence band spectra for the vapour and liquid phases of both sample systems. The resulting overall picture gives insight into the water/methanol concentrations of the vapour and liquid phases as well as into the local electronic structure of the pertinent molecular clusters under consideration, with a special emphasis on methanol as the simplest amphiphilic molecule capable of creating hydrogen bonds. © 2019 Elsevier B.V.

  • Writing chemical patterns using electrospun fibers as nanoscale inkpots for directed assembly of colloidal nanocrystals

    Kiremitler N.B., Torun I., Altintas Y., Patarroyo J., Demir H.V., Puntes V.F., Mutlugun E., Onses M.S. Nanoscale; 12 (2): 895 - 903. 2020. 10.1039/c9nr08056b. IF: 6.970

    Inorganic Nanoparticles

    Applications that range from electronics to biotechnology will greatly benefit from low-cost, scalable and multiplex fabrication of spatially defined arrays of colloidal inorganic nanocrystals. In this work, we present a novel additive patterning approach based on the use of electrospun nanofibers (NFs) as inkpots for end-functional polymers. The localized grafting of end-functional polymers from spatially defined nanofibers results in covalently bound chemical patterns. The main factors that determine the width of the nanopatterns are the diameter of the NF and the extent of spreading during the thermal annealing process. Lowering the surface energy of the substrates via silanization and a proper choice of the grafting conditions enable the fabrication of nanoscale patterns over centimeter length scales. The fabricated patterns of end-grafted polymers serve as the templates for spatially defined assembly of colloidal metal and metal oxide nanocrystals of varying sizes (15 to 100 nm), shapes (spherical, cube, rod), and compositions (Au, Ag, Pt, TiO2), as well as semiconductor quantum dots, including the assembly of semiconductor nanoplatelets. © 2019 The Royal Society of Chemistry.