Computational investigation of the fundamental physical properties of lead-free halide double perovskite Rb₂NaCoX₆ (X = Cl, Br, and I) materials: Potential prospects for sustainable energy

We have undertaken an ab initio investigation of emerging metal lead-free halide double perovskite materials for renewable energy applications using the WIEN2k simulation code. These materials have garnered significant attention from the research community due to their potential utility in electronic devices. Through an analysis of their electronic structure, we have ascertained that these materials exhibit characteristics of direct band gap semiconductors, falling within the energy range spanning 0.755 to 1.825eV. Furthermore, to check their suitability for use in photovoltaic devices, optical properties have been investigated. The thermoelectric potential of these materials has been explored using the BoltzTraP simulation code. The study of thermoelectric parameters indicates that the studied materials are effective thermoelectric materials with a strong potential for n-type doping. Additionally, thermodynamic parameters have been investigated to check their thermal stability, required to make them promising candidates for a wide range of renewable energy applications.