Staff directory



  • Incorporation of Counter Ions in Organic Molecules: New Strategy in Developing Dopant-Free Hole Transport Materials for Efficient Mixed-Ion Perovskite Solar Cells

    Zhang J., Xu B., Yang L., Mingorance A., Ruan C., Hua Y., Wang L., Vlachopoulos N., Lira-Cantú M., Boschloo G., Hagfeldt A., Sun L., Johansson E.M.J. Advanced Energy Materials; 7 (14) 2017. 10.1002/aenm.201602736. IF: 16.721

    Hole transport matertial (HTM) as charge selective layer in perovskite solar cells (PSCs) plays an important role in achieving high power conversion efficiency (PCE). It is known that the dopants and additives are necessary in the HTM in order to improve the hole conductivity of the HTM as well as to obtain high efficiency in PSCs, but the additives can potentially induce device instability and poor device reproducibility. In this work a new strategy to design dopant-free HTMs has been presented by modifying the HTM to include charged moieties which are accompanied with counter ions. The device based on this ionic HTM X44 dos not need any additional doping and the device shows an impressive PCE of 16.2%. Detailed characterization suggests that the incorporated counter ions in X44 can significantly affect the hole conductivity and the homogeneity of the formed HTM thin film. The superior photovoltaic performance for X44 is attributed to both efficient hole transport and effective interfacial hole transfer in the solar cell device. This work provides important insights as regards the future design of new and efficient dopant free HTMs for photovotaics or other optoelectronic applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • Baselines for Lifetime of Organic Solar Cells

    Gevorgyan S.A., Espinosa N., Ciammaruchi L., Roth B., Livi F., Tsopanidis S., Züfle S., Queirós S., Gregori A., Benatto G.A.D.R., Corazza M., Madsen M.V., Hösel M., Beliatis M.J., Larsen-Olsen T.T., Pastorelli F., Castro A., Mingorance A., Lenzi V., Fluhr D., Roesch R., Maria Duarte Ramos M., Savva A., Hoppe H., Marques L.S.A., Burgués I., Georgiou E., Serrano-Luján L., Krebs F.C. Advanced Energy Materials; 6 (22, 1600910) 2016. 10.1002/aenm.201600910. IF: 15.230

    The process of accurately gauging lifetime improvements in organic photovoltaics (OPVs) or other similar emerging technologies, such as perovskites solar cells is still a major challenge. The presented work is part of a larger effort of developing a worldwide database of lifetimes that can help establishing reference baselines of stability performance for OPVs and other emerging PV technologies, which can then be utilized for pass-fail testing standards and predicting tools. The study constitutes scanning of literature articles related to stability data of OPVs, reported until mid-2015 and collecting the reported data into a database. A generic lifetime marker is utilized for rating the stability of various reported devices. The collected data is combined with an earlier developed and reported database, which was based on articles reported until mid-2013. The extended database is utilized for establishing the baselines of lifetime for OPVs tested under different conditions. The work also provides the recent progress in stability of unencapsulated OPVs with different architectures, as well as presents the updated diagram of the reported record lifetimes of OPVs. The presented work is another step forward towards the development of pass-fail testing standards and lifetime prediction tools for emerging PV technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim