Novel A ₂ MgZnX ₆ halide double perovskites: Stable and non-toxic materials for solar energy harvesting

This study employs density functional theory (DFT) to investigate the structural, mechanical, electronic, and optical properties of lead-free double halide perovskites A 2 MgZnX 6 ([Formula: see text], Br; [Formula: see text], Cs). All crystallize in a cubic Fm-3 m structure. Band structures confirm semiconducting behavior with direct bandgaps: Rb 2 MgZnCl 6 (2.358[Formula: see text]eV), Rb 2 MgZnBr 6 (1.420[Formula: see text]eV), Cs 2 MgZnCl 6 (2.451[Formula: see text]eV), and Cs 2 MgZnBr6 (1.337[Formula: see text]eV). Elastic constants suggest brittle behavior for three compounds, while Cs 2 MgZnCl 6 is ductile. High stiffness, melting points, and thermal stability indicate strong bonding. Optical studies show low energy loss and strong absorption near 2[Formula: see text]eV and 10[Formula: see text]eV, supporting optoelectronic applications.