Phase Transition and Band Gap Regulation by Halogen Substituents on the Organic Cation in Organic–Inorganic Hybrid Perovskite Semiconductors |
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Authors: | Ying-Jie Cao Lin Zhou Lei He Ping-Ping Shi Prof. Dr. Qiong Ye Prof. Dr. Da-Wei Fu |
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Affiliation: | Ordered Matter Science Research Center, Jiangsu Key Laboratory for Science and Applications of, Molecular Ferroelectrics, Southeast University, Nanjing, 211189 P. R. China |
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Abstract: | In the last decade, hybrid materials have received widespread attention. In particular, hybrid lead halide perovskite-type semiconductors are very attractive owing to their great flexibility in band gap engineering. Here, by using precise molecular modifications, three one-dimensional perovskite-type semiconductor materials are designed and obtained: [Me3PCH2X][PbBr3] (X=H, F, and Cl for compounds 1 , 2 , and 3 , respectively). The introduction of a heavier halogen atom (F or Cl) to [Me4P]+ increases the potential energy barrier required for the tumbling motion of the cation, hence achieving the transformation of the phase transition temperature from low temperature (192 K) to room temperature (285 K) and high temperature (402.3 K). Moreover, the optical band gaps reveal a broadening trend with 3.176 eV, 3.215 eV, and 3.376 eV along the H→F→Cl series, which is attributed to the formation of the structural distortion. |
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Keywords: | band gap adjustment halogen substitution organic–inorganic hybrid perovskites semiconductors structure elucidation |
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