A time-dependent density functional study on optical response in all-inorganic lead-halide perovskite nanostructures |
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Authors: | Bofeng Zhang Hong Zhang Jiahe Lin Xinlu Cheng |
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Affiliation: | 1. College of Physics, Sichuan University, Chengdu, China;2. School of Science, Jimei University, Xiamen, China Contribution: Formal analysis, Writing - review & editing;3. Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu, China Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, China Contribution: Resources, Supervision |
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Abstract: | Recently, all-inorganic perovskite nanostructures have become a hot research topic due to their unique optical response and novel properties. Here, we theoretically study the optical response in Cs2PbX4 and CsPb2X5 (X = Cl, Br, and I) nanostructures. First, to study the ground state, we calculate the band structures of the periodic system using the HSE06 method, which shows that all those periodic perovskites possess the direct band gaps, with distribution from 2.225 to 3.536 eV. Their valence band maximum are mainly contributed from both halogen and lead atoms, while the conduction band minimum are mainly contributed from lead atoms. Then, we study the excited state using the time-dependent density functional theory method and find that, with the increase of halogen atom radius, the photogenerated carrier concentrations in perovskite nanostructures become larger, while the surface plasmon resonance becomes localized rather than long-range. Moreover, through the analysis of photocurrent and local field enhancement, Cs2PbX4 and CsPb2X5 nanostructures exhibit nearly 40 μA photocurrent along the direction of optical polarization. Besides, by regulating the different anions, we predict that field enhancement in Cs2PbI4 and CsPb2I5 share a much stronger distribution at both the center and border parts of Pb-I planes due to localized plasmon resonance, while other perovskites are distributed at the edge parts of Pb-I planes, caused by long-range plasmon resonance. Our research shows that all-inorganic perovskite nanostructures are great candidate materials for developing optoelectronic devices working in high-frequency and high-energy regions and improving their application in sensitive detection and sensors. |
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Keywords: | all-inorganic perovskite field enhancement photocurrent plasmon resonance TDDFT method Cs2PbX4 and CsPb2X5 (X = Cl, Br, and I) nanostructures |
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