Exploring the photovoltaic potential of Cs2AgBX6 (BBi, Sb; X=Br, Cl) double perovskites: A computational study

Double perovskite materials have shown significant potential in addressing the toxicity and instability issues of lead halide perovskites in practical applications. In particular, Cs₂AgBX₆ (BBi, Sb; X = Br, Cl) has attracted considerable attention as an efficient and environmentally friendly alternative to lead-based perovskites. In this study, Cs₂AgBX₆ is selected as the light-absorbing layer for solar cells. Structural calculations reveal that Cs₂AgBX₆ is an indirect bandgap semiconductor, with a bandgap ranging from 0.9 to 1.8 eV, exhibiting excellent photovoltaic performance, particularly within the visible light absorption range. Specifically, antimony-based perovskites demonstrate an outstanding optical absorption coefficient of 5 × 10⁵ cm⁻¹. Moreover, the Cauchy pressure significantly influences the material's elasticity and brittleness, with empirical results indicating that all four materials possess good elastic properties. The mechanical stability of the materials is described in terms of Young's modulus, Poisson's ratio, and other mechanical parameters. Simulation results for the solar cell show that Cs₂AgBX₆ achieves a power conversion efficiency (PCE) of up to 14.28 %. Therefore, this study not only demonstrates the immense potential of Cs₂AgBX₆ in photovoltaic applications but also paves the way for its further development in device applications.