Impact of Cs Substitution on the Optoelectronic Properties of MASnI₃ Perovskite: A DFT study

¹ Sultan Moulay Slimane University of Beni Mellal, Multidisciplinary Research and Innovation Laboratory, FP Khouribga, BP. 145, 2500 Khouribga, Morocco
² LRPSI, Faculty of Polydisciplinary, Sultan Moulay Slimane University, B.P 592, 23000, Beni Mellal- Morocco
³ Laboratory of Engineering in Chemistry and Physics of Matter (LIPCM), Faculty of Sciences and Technics, Sultan Moulay Slimane University, B.P 523, 23000 Beni Mellal, Morocco
⁴ PSES, ERC, Ecole Normale Supérieur, Mohammed V University in Rabat, P. O. Box: BP5118 Takkadoum Rabat- 10000, Morocco

^* Corresponding author: abdelhafid.najim@usms.ma

Abstract

The electronic structures and optical characteristics of pristine MASnI₃ (MA = CH₃NH₃) perovskite and cesium (Cs)-substituted MASnI₃ were investigated using density functional theory (DFT). The structures were constructed, optimized, and analyzed with the CASTEP code to obtain their band structures and optical properties. This perovskite material is of great interest for next-generation optoelectronic devices. Substituting Cs in MASnI₃ perovskite reduces the band gap from 1.051 eV to 0.984 eV and alters the optical response. The incorporation of Cs into the MASnI₃ perovskite significantly influences its electronic and optical characteristics, indicating that Cs substitution is a promising strategy for tuning these properties.