Tuning the electronic, optical, and thermal properties of cubic perovskites CsPbCl3-nBrn (n=0, 1, 2, and 3) through altering the halide ratio

The metal halide-based perovskites have been used for photovoltaic device applications owing to their outstanding properties, low-temperature solution, and cheap manufacturing cost. The electronic, optical, mechanical, and thermal properties of CsPbCl3-nBrn (where n = 0, 1, 2, and 3) have been calculated using first-principles density functional theory (FP-DFT) calculations. The Perdew, Burke, and Enzerofe (PBE) exchange-correlation functional has been considered for the structural calculations. The calculated electronic properties of CsPbCl3-nBrn (where n = 0, 1, 2, and 3) suggest that these materials are direct bandgap semiconductors at normal pressure. The bandgap of CsPbCl3 has been decreased by substituting the Cl atom with the Br atom. Moreover, it is observed that the values of the bandgap of CsPbCl3-nBrn (where n = 0, 1, 2, and 3) materials diminished by rising the pressure, even the semiconductor phase transitioned to the metallic phase under high pressure. The narrowing bandgap enhances the strong light absorption properties of these materials in visible spectrum region. Elastic constants and thermal characteristics obtained for these compounds also demonstrate their structural integrity. Therefore, these compounds can be the promising candidates for optoelectronic and solar cell applications.