Enhanced Charge Transport in A-site Ordered Perovskite Derivatives A2A'Bi2I9 (A = Cs; A'= Ag, Cu): A First-Principles Study
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915181547749376 |
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| author | Li, Shuhan Song, Siyu Lv, Peng Wang, Shihao Hong, Jiawang Tang, Gang |
| author_facet | Li, Shuhan Song, Siyu Lv, Peng Wang, Shihao Hong, Jiawang Tang, Gang |
| contents | Recent experiments have synthesized Cs2AgBi2I9 by partially substituting Cs+ with Ag+ at the A-site of Cs3Bi2I9, resulting in enhanced charge transport properties compared to Cs3Bi2I9. However, the atomic-scale mechanisms behind this enhancement remain unclear. In this work, we investigate the carrier transport mechanisms in Cs2A'Bi2I9 (A' = Ag, Cu) using first-principles calculations and Boltzmann transport calculations. Our results reveal that A-site ordered Cs2A'Bi2I9 exhibits carrier mobilities that are 3-4 times higher than those of Cs3Bi2I9 within the 100-500 K temperature range. We identify polar phonon scattering as the dominant mechanism limiting mobility. Furthermore, the enhanced out-of-plane carrier mobility in Cs2A'Bi2I9, particularly between 100 and 200K, leads to reduced mobility anisotropy. These improvements are mainly due to the shorter A'-I bond lengths and increased Ag+/Cu+ s-I p orbital coupling. Notably, substitution with Cu+ results in a further reduction in the band gap and enhanced hole mobility compared to Ag+ substitution in Cs3Bi2I9. Further analysis reveals that the significant increase in carrier mobility in Cs2A'Bi2I9 can be largely explained by the smaller carrier effective masses (m*) and weaker Fröhlich coupling strengths (α), resulting in a lower polar mass α(m*/me), compared to Cs3Bi2I9. Our study provides valuable insights into the transport properties of Bi-based perovskite derivatives, paving the way for their future applications in optoelectronic devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_02478 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Enhanced Charge Transport in A-site Ordered Perovskite Derivatives A2A'Bi2I9 (A = Cs; A'= Ag, Cu): A First-Principles Study Li, Shuhan Song, Siyu Lv, Peng Wang, Shihao Hong, Jiawang Tang, Gang Materials Science Recent experiments have synthesized Cs2AgBi2I9 by partially substituting Cs+ with Ag+ at the A-site of Cs3Bi2I9, resulting in enhanced charge transport properties compared to Cs3Bi2I9. However, the atomic-scale mechanisms behind this enhancement remain unclear. In this work, we investigate the carrier transport mechanisms in Cs2A'Bi2I9 (A' = Ag, Cu) using first-principles calculations and Boltzmann transport calculations. Our results reveal that A-site ordered Cs2A'Bi2I9 exhibits carrier mobilities that are 3-4 times higher than those of Cs3Bi2I9 within the 100-500 K temperature range. We identify polar phonon scattering as the dominant mechanism limiting mobility. Furthermore, the enhanced out-of-plane carrier mobility in Cs2A'Bi2I9, particularly between 100 and 200K, leads to reduced mobility anisotropy. These improvements are mainly due to the shorter A'-I bond lengths and increased Ag+/Cu+ s-I p orbital coupling. Notably, substitution with Cu+ results in a further reduction in the band gap and enhanced hole mobility compared to Ag+ substitution in Cs3Bi2I9. Further analysis reveals that the significant increase in carrier mobility in Cs2A'Bi2I9 can be largely explained by the smaller carrier effective masses (m*) and weaker Fröhlich coupling strengths (α), resulting in a lower polar mass α(m*/me), compared to Cs3Bi2I9. Our study provides valuable insights into the transport properties of Bi-based perovskite derivatives, paving the way for their future applications in optoelectronic devices. |
| title | Enhanced Charge Transport in A-site Ordered Perovskite Derivatives A2A'Bi2I9 (A = Cs; A'= Ag, Cu): A First-Principles Study |
| topic | Materials Science |
| url | https://arxiv.org/abs/2503.02478 |