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 (2.358Formula: see texteV), Rb 2 MgZnBr 6 (1.420Formula: see texteV), Cs 2 MgZnCl 6 (2.451Formula: see texteV), and Cs 2 MgZnBr6 (1.337Formula: see texteV). 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 2Formula: see texteV and 10Formula: see texteV, supporting optoelectronic applications.