Compositional Variation in FAPb(1-x)Sn(x)I(3) and Its Impact on the Electronic Structure: A Combined Density Functional Theory and Experimental Study
| Autor: | Simon Kahmann, Zehua Chen, Oleh Hordiichuk, Olga Nazarenko, Shuyan Shao, Maksym V. Kovalenko, Graeme R. Blake, Shuxia Tao, Maria A. Loi |
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| Přispěvatelé: | Photophysics and OptoElectronics, Solid State Materials for Electronics, Materials Simulation & Modelling, Computational Materials Physics, Center for Computational Energy Research |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | ACS Applied Materials & Interfaces, 14(30), 34253-34261. AMER CHEMICAL SOC ACS Applied Materials and Interfaces, 14(30). American Chemical Society ACS Applied Materials & Interfaces, 14 (30) ACS Applied Materials and Interfaces, 14(30), 34253-34261. AMER CHEMICAL SOC |
| ISSN: | 1944-8244 1944-8252 |
| Popis: | Given their comparatively narrow band gap, mixed Pb–Sn iodide perovskites are interesting candidates for bottom cells in all-perovskite tandems or single junction solar cells, and their luminescence around 900 nm offers great potential for near-infrared optoelectronics. Here, we investigate mixed FAPb1–xSnxI3 offering the first accurate determination of the crystal structure over a temperature range from 293 to 100 K. We demonstrate that all compositions exhibit a cubic structure at room temperature and undergo at least two transitions to lower symmetry tetragonal phases upon cooling. Using density functional theory (DFT) calculations based on these structures, we subsequently reveal that the main impact on the band gap bowing is the different energy of the s and p orbital levels derived from Pb and Sn. In addition, this energy mismatch results in strongly composition-dependent luminescence characteristics. Whereas neat and Sn-rich compounds exhibit bright and narrow emission with a clean band gap, Sn-poor compounds intrinsically suffer from increased carrier recombination mediated by in-gap states, as evidenced by the appearance of pronounced low-energy photoluminescence upon cooling. This study is the first to link experimentally determined structures of FAPb1–xSnxI3 with the electronic properties, and we demonstrate that optoelectronic applications based on Pb–Sn iodide compounds should employ Sn-rich compositions. ACS Applied Materials & Interfaces, 14 (30) ISSN:1944-8244 ISSN:1944-8252 |
| Databáze: | OpenAIRE |
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