Study of structural, mechanical, thermal, and electronic structure properties of A2SnCl6 (A = Cs, Rb) perovskites for energy generation applications

The structural, mechanical, thermal, and electronic structure properties of lead-free vacancy-ordered perovskites A(2)SnCl(6) (A = Cs, Rb) were investigated by first-principles calculations under pressure in the DFT framework. DFT is used to study the effect of pressure (0-40 GPa) on these properties of A2SnCl6 (A = Cs, Rb) perovskites. The mechanical parameters show that these two perovskites in nature are mechanically stable, anisotropic, and ductile. It is shown that, as pressure increases, the electronic band gap of Cs2SnCl6 2 SnCl 6 and Rb2SnCl6 2 SnCl 6 increases from 3.495 eV to 4.958 eV and 3.446 eV to 4.722 eV, respectively. Electronic structure calculations show that Sn s orbitals and halogen Cl p orbitals mainly form the conduction band through combination, while the valence band consists only of halogen Cl p orbitals. The mechanical and electronic properties analysis proposes that these two perovskites are potential candidates for optoelectronic applications that work under changing pressure and altitude.