Pressure‐Induced Emission Enhancement,Band‐Gap Narrowing,and Metallization of Halide Perovskite Cs3Bi2I9 |
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Authors: | Long Zhang Chunming Liu Lingrui Wang Prof Cailong Liu Prof Kai Wang Prof Bo Zou |
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Institution: | 1. State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, China;2. Institute of Atomic and Molecular Physics, Jilin University, Changchun, China;3. Institute of Atomic and Molecular Physics and State Key Laboratory of Superhard Materials, Jilin University, Changchun, China |
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Abstract: | Low‐toxicity, air‐stable bismuth‐based perovskite materials are attractive substitutes for lead halide perovskites in photovoltaic and optoelectronic devices. The structural, optical, and electrical property changes of zero‐dimensional perovskite Cs3Bi2I9 resulting from lattice compression is presented. An emission enhancement under mild pressure is attributed to the increase in exciton binding energy. Unprecedented band gap narrowing originated from Bi?I bond contraction, and the decrease in bridging Bi‐I‐Bi angle enhances metal halide orbital overlap, thereby breaking through the Shockley–Queisser limit under relatively low pressure. Pressure‐induced structural evolutions correlate well with changes in optical properties, and the changes are reversible upon decompression. Considerable resistance reduction implies a semiconductor‐to‐conductor transition at ca. 28 GPa, and the final confirmed metallic character by electrical experiments indicates a wholly new electronic property. |
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Keywords: | band gap bismuth metallization perovskites photoluminescence |
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