Decreasing toxicity and increasing photoconversion efficiency by Sn-substitution of Pb in 5-ammonium valeric acid-based two-dimensional hybrid perovskite materials
| Autor: | Hardik L. Kagdada, Arnulf Materny, Dheeraj K. Singh |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Physical Chemistry Chemical Physics. 24:23226-23235 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d2cp02997a |
| Popis: | The toxicity of Pb in halide-based hybrid perovskite materials stands in the way of their more extensive use, despite their excellent optical properties, high stability and very good photoconversion efficiency. The presented work focuses on addressing the toxicity issues in 2D perovskites. We use 5-ammonium valeric acid (AVA) as an organic spacer and partially or completely eliminate Pb by Sn and apply first principles-based density functional theory (DFT) calculations to determine the properties of these systems. Structural insights are gained, which predict the major changes in the inorganic framework including the metal-halide bond length and the bridging angle between two octahedral configurations. The replacement of Pb by Sn leads to a drastic reduction of the electronic band gap from 1.84 to 1.04 eV. Increasing the Sn content results in Sn-I bonds being stronger than the Pb-I bonds, which entails strong s-p coupling. The calculated effective masses of excitons decrease by up to ∼23% in the case of lead-free perovskites, which can be attributed to the more dispersive band edges due to stronger s-p coupling. The reduction of the effective masses of the charge carriers and the electronic band gap results in high electrical conductivity for the AVA |
| Databáze: | OpenAIRE |
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