The first-principle study of mechanical, optoelectronic and thermoelectric properties of CsGeBr3 and CsSnBr3 perovskites

The mechanical, optical, thermoelectric and thermodynamic characteristics of Cesium based bromides are systematically studied using the most comprehensive DFT based Wien2k code for elucidating the energy renewable device applications. The mechanical, thermodynamic and structural stabilities of the studied perovskites are revealed in terms of Born mechanical stability criteria, enthalpy of formation and Goldschmidt's tolerance factor, respectively. The ductile/brittle nature, anisotropy, wave velocity and Debye temperatures are computed to illustrate the mechanical nature. The optical parameters have been found highly sensitive to the exhibited band gap lying within visible energy. The large thermoelectric efficiency has been found that is responsible to exhibit optimum values of the power factors and the thermal conductivity. Furthermore, the specific heat capacity, Hall coefficient, magnetic susceptibility and electron density are also described in detail. Hence, the studied perovskites showing band gap in visible region have been found suitable for commercial applications in Solar cell, optoelectronic and thermoelectric devices.