The Effects of Pressure on Tetragonal RbPbBr ₃ Perovskite for Photovoltaic Applications: A Computational Study

ABSTRACT All inorganic perovskite materials have received significant attention in the photovoltaic devices due to their remarkable optoelectronic properties. Although the efficiency of has been reported to increase using various electron transport layers, it is also crucial to improve the performance of the absorber layer of . In this work, density functional theory (DFT) and ab initio molecular dynamics (AIMD) were performed for investigating the structural, electronic, and optical properties of tetragonal perovskite under different pressure. The results indicate that the bandgap can be tuned from to eV under the application of pressure from to GPa, using Heyd–Scuseria–Ernzerhof (HSE) hybrid functional including spin–orbit coupling (SOC) effect. The change in the bandgap is primarily influenced by variations in the Pb‐Br‐Pb bond angle and the short and the long bond length of Pb‐Br under pressure ranging from to GPa. A suitable bandgap of eV can be achieved at a pressure of GPa, making it promising for the photovoltaic applications. The anharmonic phonon spectra at K indicates the structural stability under different pressure considered. The narrowing of the bandgap implies a redshift in the absorption spectra. Moreover, the effective masses of conduction electrons and holes decrease, and excitons become weaker with increasing pressure. The exciton type changes from Frenkel to Mott–Wannier at pressure beyond GPa. These results are crucial for understanding the effects of pressure on the photovoltaic properties of tetragonal perovskite, and this can guide the experiments aimed at improving the photovoltaic performance of all inorganic perovskites.