ICMAB INVITED SEMINAR

Speaker: Wiktor Lewandowski, Faculty of Chemistry at the University of Warsaw, Poland

Abstract:Thin films exhibiting chiroptical properties hold great potential for emerging photonic technologies relying on the emission or detection of circularly polarized light. However, further efforts are required to enhance, tune, and actively regulate thin films'chiroptical activity to fully realize their potential. Recently, we addressed these challenges by introducing a liquid crystal-assisted method forfabricating chiroptical thin films.

The developed method relies on LCs forming morphologically chiral structures, such as helical nanofibers, to guide the assembly ofnanoparticles. We have shown that this methodology is universal to Au nanoparticles of different sizes and shapes, Au nanoclusters, perovskite nanocrystals, and other nanoinclusions.

Notably, these chiral assemblies exhibit high dissymmetry factors (g-factor on the order of 0.2), which we have proven originates from the additive molecular and supramolecular chirality. Moreover, the materials we achieve can respond to thermal and light stimuli. We recently used these materials to fabricate thin films with a pixelated structure, where each pixel exhibits on-demand controlled plasmonic and electronic handedness.

Overall, our approach towards achieving chiral nanomaterials offers advantages for communication, display, and anticounterfeiting technologies.

Short Bio: Wiktor Lewandowski completed undergraduate studies at the University of Warsaw in 2008 with MSc degrees in Organic Chemistry (at the Faculty of Chemistry) and Biotechnology (at the Faculty of Biology). He obtained PhD degree at the University of Warsaw in an International PhD Programme in 2013. He gained international experience working at Prof. Swager's laboratory at MIT, USA, and with Prof. Luis Liz-Marzan, CICbiomaGUNE, Spain. He was awarded several prestigious stipends and grants from the Polish scientific council. He is currently leading a group at the University of Warsaw focused on developing nanomaterials for photonic and medical applications, combining organic and inorganic chemistry expertise.