A comprehensive DFT study of the optoelectronic, mechanical, and thermoelectric properties of Rb[formula omitted]NaScCl[formula omitted] double perovskite implying different pressures

Abstract

Double perovskite materials possess exceptional properties that render them suitable for application in various sectors and technologies. In this study, we explore the electronic, optical, thermoelectric, and mechanical properties of Rb2NaScCl6, a double perovskite devoid of toxicity, across a wide pressure range from 0 GPa to 200 GPa using density functional theory. Structural and mechanical stabilities are evaluated through tolerance and octahedral factors, as well as elastic constants. The direct band gap of this material is found to be 3.91 eV at 0 GPa pressure. The band gap of this material increases with pressure up to 20 GPa and its value is 4.41 eV at the pressure of 20 GPa; however, its value decreases after that pressure and becomes 2.55 at 200 GPa pressure. Importantly, the optical properties demonstrate that the absorption coefficient lies mostly within the ultra-violet range at normal atmospheric pressure; however, it displays effective absorption in the visible range at high pressure. In addition, the material’s ductile nature is verified using Pugh’s ratio, Cauchy’s pressure, and Poisson’s ratio at different pressures. Moreover, the stiffness of the material increases along with the raising of pressure. Finally, an exploration of the thermoelectric properties reveals that the material demonstrates favorable thermoelectric attributes. Therefore, our material exhibits promising candidates for utilization in diverse sectors, particularly in the realm of new energy production applications.