Investigation of lead-free halide K2AgSbBr6 double Perovskite's structural, electronic, and optical properties using DFT functionals

Abstract

In recent years, the remarkable photoelectric properties exhibited by perovskite materials have stimulated scientific inquiry, prompting investigations into novel perovskite variants and derivatives characterized by environmentally friendly attributes and robust stability. These materials offer potential as efficient solar light harvesters. Our study concentrates on elucidating the structural, electronic, and optical properties of the newly discovered stable lead-free double perovskite K2AgSbBr6, employing first-principles methods rooted in Density Functional Theory (DFT). We confirm the structural and dynamical stabilities of K2AgSbBr6 through computational analysis. Our calculations reveal that the examined compound exhibits characteristics of an indirect semiconductor, with a band gap of 0.857 eV (L-X). Notably, our findings demonstrate that the compound displays enhanced photovoltaic performance, as evidenced by elevated optical absorption coefficients exceeding 105 cm−1, surpassing those of CH3NH3PbI3. These results underscore the potential of K2AgSbBr6, a novel lead-free double perovskite, as a promising candidate for exceptional light-absorbing material spanning the UV and visible spectra.

Keywords

• DFT calculations
• Double perovskite
• Opto-electronic properties
• Density of states
• Band gap
• Dielectric function