Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 28: Perovskite and Photovoltaics 3
CPP 28.1: Vortrag
Mittwoch, 7. September 2022, 15:00–15:15, H38
Optically-Induced Long-lived Chirality Memory in the Color Tunable Chiral Lead-Free Semiconductor (R)/(S)-CHEA4Bi2BrxI10-x (x = 0 - 10) — •Shangpu Liu1, Markus Heindl1, Natalie Fehn2, Sebastián Caicedo-Dávila1, Silva Kronawitter2, Gregor Kieslich2, David Egger1, Aras Kartouzian2, and Felix Deschler1 — 1Walter Schottky Institute and Department of Physics, TUM, Garching, Germany — 2Catalysis Research Center, TUM, Garching, Germany
Hybrid organic-Inorganic networks that incorporate chiral molecules have attracted great attention due to their potential in semiconductor lighting applications and optical communication. Here we introduce the chiral organic molecules (R/S)-CHEA into bismuth-based structures with an edge-sharing octahedral motif, to synthesize chiral (R/S)-CHEA4Bi2BrxI10-x crystals and thin films. Using single-crystal X-ray diffraction measurements and density-functional theory calculations, we identify crystal and electronic band structures. We investigate the material optical properties and find circular dichroism, which we tune by the bromide-iodide ratio over a wide wavelength range from 300-500 nm. Further, we employ transient absorption spectra and time-correlated single photon counting to investigate charge carrier dynamics, which show long-lived excitations with unexpected optically-induced chirality memory up to 10s of nanosecond timescales. Our demonstration of chirality memory in a color-tunable and chiral lead-free semiconductor opens a new avenue for the discovery of high-performance spintronic materials with optical functionalities.