The Effect of Phase Changes on Optoelectronic Properties of Lead-Free CsSnI3 Perovskites

作者：Dilshod Nematov, Amondulloi Burkhonzoda, Mekhrdod S. Kurboniyon, Zafari Umar, Kholmirzo Kholmurodov, M.G. Brik, Tomoyuki Yamamoto, Farhod Shokir · 发表于：Journal of Electronic Materials · 年份：2025 · DOI：10.1007/s11664-024-11683-9 · 被引用次数：10 · 研究领域：Perovskite Materials and Applications、Chalcogenide Semiconductor Thin Films、Optical properties and cooling technologies in crystalline materials

Abstract First-principles calculations were carried out within the framework of density functional theory to investigate the influence of phase changes on the electronic and optical properties of CsSnI 3 . The lattice parameter and band gap of four different phases, i.e., α-, β-, γ-, and δ-phases, of CsSnI 3 are estimated by employing different exchange–correlation functionals in order to explore their ability to reproduce geometric and electronic structures adequately. Comparison of the calculated total energies shows the non-perovskite orthorhombic (δ-phase) modification of CsSnI 3 is the most stable, followed by the orthorhombic (γ-CsSnI 3 ) perovskite phase. Thermal stability calculations in the form of temperature dependence of entropy as well as the absence of imaginary frequencies in the phonon dispersion diagrams also confirmed the dynamical stability of the δ-CsSnI 3 . The influence of the structural phase changes on the band gap and Fermi level shifts of CsSnI 3 were assessed. Contribution of the electronic states on the formation of the valence and conduction band of four phases of CsSnI 3 were determined, which were calculated using various exchange–correlation functionals, including the high-precision hybrid functional HSE06, and compared with available experimental ones. The calculated energy band distribution diagrams showed that all three perovskite modifications of CsSnI 3 have direct transitions, while δ-CsSnI 3 has an indirect transition. It was found that ...