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HL: Fachverband Halbleiterphysik
HL 4: Perovskite and Photovoltaics I (joint session HL/KFM)
HL 4.3: Vortrag
Montag, 18. März 2024, 10:00–10:15, EW 203
Enhanced Circular Dichroism and Polarized Emission in an Achiral, Low Bandgap Bismuth Iodide Perovskite — •Philip Klement1, Jakob Möbs2, Gina Stuhrmann3, Lukas Gümbel1, Marius Müller1, Johanna Heine2, and Sangam Chatterjee1 — 1Institute of Experimental Physics I, JLU Gießen, Germany — 2Department of Chemistry, PUM, Marburg, Germany — 3Institute of Nanotechnology (INT), KIT, Eggenstein-Leopoldshafen, Germany
Lead halide perovskites and related materials incorporating chiral organic cations exhibit intriguing properties such as chiroptical activity and chirality-induced spin selectivity enabling the generation and detection of circularly polarized light. However, understanding the structural origin of chiroptical activity presents a challenge due to macroscopic factors and experimental constraints. Here, we present the achiral perovskite derivative [Cu2(pyz)3(MeCN)2][Bi3I11] (pyz = pyrazine; MeCN = acetonitrile), which displays remarkable circular dichroism (CD) arising from the material*s noncentrosymmetric structure. CuBiI exhibits a low, direct optical band gap of 1.70 eV and both linear and circular optical activity with a substantial anisotropy factor of up to 0.16. Intriguingly, despite the absence of chiral building blocks, CuBiI exhibits a substantial degree of circularly polarized photoluminescence, reaching 4.9%. This value is comparable to the results achieved by incorporating chiral organic molecules into perovskites, typically ranging from 3 to 10% at zero magnetic field. Our findings shed light on the macroscopic origin of CD and provide valuable insights for the design of materials with high chiroptical activity.
Keywords: perovskite; polarization; dichroism; chirality