Regensburg 2022 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Perovskite and Photovoltaics 2

CPP 19.1: Hauptvortrag

Mittwoch, 7. September 2022, 09:30–10:00, H38

Elucidating the role of antisolvent polarity on the surface chemistry and optoelectronic properties of lead-halide perovskite nanocrystals — •Robert Hoye — Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom

Lead-halide perovskites (LHPs) have emerged as highly-promising contenders for light-emission applications, particularly in the form of nanocrystals (NCs), owing to their advantages of high photoluminescence quantum yield (PLQY), along with tunable, sharp emission peaks. Achieving high-quality NCs critically depends on the purification process, which often makes use of an antisolvent. Despite its important role, the mechanism by which the antisolvent influences the surface properties of the NCs is not well understood. In this talk, we examine the influence of the polarity of the antisolvent on the properties of the model NC system CsPbBrxI3-x. The antisolvents we compare are (in order of increasing polarity): methyl acetate, acetone and butanol. We find that as the polarity of the antisolvent increases, there is a greater blue-shift in the photoluminescence peak, owing to the removal of iodide. Through detailed nuclear magnetic resonance measurements, we find that this occurs due to more polar antisolvents having a higher propensity to induce a condensation reaction between the oleic acid and oleylamine ligands on the NCs, leading to their removal in the form of amides, which leads to the removal of surface iodides. This work shows that minimising surface damage to LHP NCs requires the selection of low polarity antisolvents.