The role of the A-cations in the polymorphic stability and optoelectronic properties of lead-free ASnI3 perovskites
| Autor: | Malladi Srikanth, Rafael Besse, Juarez L. F. Da Silva, Mailde S. Ozório |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Band gap General Physics and Astronomy Perovskite solar cell 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences CÉLULAS SOLARES Formamidinium Chemical physics Phase (matter) Density of states Density functional theory Physical and Theoretical Chemistry 0210 nano-technology Electronic band structure Perovskite (structure) |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | Tin-based ASnI3 perovskites have been considered excellent candidates for lead-free perovskite solar cell applications; however, our atomistic understanding of the role of the A-cations, namely, CH3NH3 (methylammonium, MA), CH3PH3 (methylphosphonium, MP) and CH(NH2)2 (formamidinium, FA), in the physical chemistry properties is far from satisfactory. For the first time, we report a density functional theory investigation of the MPSnI3 perovskite and non-perovskite phases as well as their comparison with the MASnI3 and FASnI3 phases, where we considered the role of the A-cation orientations in the structural stability of the ASnI3 phases. The orthorhombic structure is the most stable studied phase, which agrees with experimentally reported phase-transition trends. In contrast with the cation size and the weak hydrogen bonding interactions, which contribute to structural cohesion between the inorganic framework and A-cation, the dipole–dipole interactions play an important role to drive the structures to the lowest energy configurations. From our analysis, the inorganic framework dominates the optical properties, band structure, and density of states around the band edges. Broader absorption and smaller band gap energies occur for the perovskite structures compared to the low-dimensional hexagonal/pseudo-hexagonal non-perovskites. |
| Databáze: | OpenAIRE |
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