DFT-based modelling of optoelectronic, thermodynamic and thermoelectric properties in copper-based perovskites CuMCl₃ (M: Ca and Sr) for thermoelectric applications

The discovery of new materials with fascinating features is significant for the scientific and industrial expansion of optoelectronic and thermoelectric uses. Through density functional theory (DFT), the physical features of CuMCl 3 (M= Ca, Sr) perovskites are investigated using the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) technique within Wien2k code. The structural features enumerated with the help of Perdew–Burke–Ernzerhof Generalized Gradient Approximation (GGA-PBE) were found in good compliance with previous theoretical results. Meanwhile, the calculated formation energy values confirm the thermodynamic stability and the ability to be synthesized. For accurate calculations and overcome the GGA band gap underestimation, the rest of physical features have been explored using the Heyd–Scuseria–Ernzerhof hybrid (HSE) approximation. The electronic characteristics revealed the semiconductor nature of both the compounds studied, with an indirect band gap (M - Γ) of 2.56 eV and 2.46 eV for CuCaCl 3 and CuSrCl 3 , correspondingly. In addition, a detailed study of optical features including dielectric function (real and imaginary portions), absorption coefficient, optical reflectivity, optical refractivity and extinction coefficient has been conducted. It has been found that perovskites under investigation reveal high values of absorption coefficient. The thermodynamic characteristics were evaluated using the Gibbs2 software platform at specific pressure values and temperature in the range of 0-700K. The thermoelectric features of the selected materials have been investigated in the temperature span 50–1000 K. The large figure of merit and the Seebeck coefficient values of the selected perovskites disclose its potential applications in thermoelectric devices.