Study of Optical, Thermoelectric, and Mechanical Behaviors of Double PerovskitesCs2SnVX6(X = Cl, Br, I) for Renewable Energy

Abstract Double perovskites are emerging materials for solar cells and renewable energy applications. Here this research emphasizes the optical, transport, and mechanical characteristics of Cs2SnVX6 (X = Cl, Br, I) for renewable energy. The structural and dynamic stabilities of these double perovskites in the cubic phase have been ensured by the tolerance factor (0.94, 0.93, 0.91) and the Ab initio molecular dynamic (AIMD) simulation. Furthermore, formation energy and elastic constants have also been reported, which provide evidence of thermodynamic and mechanical stability. The band gaps analyzed by TB-mBJ potential are 1.48 eV, 1.29 eV, and 0.22 eV for the Cs2SnVCl6, Cs2SnVBr6, and Cs2SnVI6, respectively. The band gap of Cs2SnVBr6 is standard for solar cells. The absorption band exists in the visible to infrared zone, with minimal optical losses. The transport behavior has been addressed through the BoltztraP code, whose large thermoelectric performance has been confirmed by the figure of merit (1.10, 0.90, 0.65) at 300K, and ultralow lattice thermal conductivity. From mechanical analysis, it is assumed that Cs2SnVCl6 has a ductile nature (B/G = 2.0) while Cs2SnVBr6 and Cs2SnVI6 have a brittle nature (B/G = 1.26, 0.94). Moreover, their hardness, large Debye, and melting temperature are also important for device fabrication.