The screening of the potential features of potassium-based K2BGaI6 (B = Tl, Rb) double perovskites for eco-friendly technologies: a first-principles study.

Utilizing first-principles calculations, this study explores the physical characteristics of K2BGaI6 (B = Tl, Rb) double perovskites with the objective of gaining a deeper understanding of their viability for renewable applications. In evaluating the phase stability, we calculated the formation enthalpies, tolerance factor and optimization energies, demonstrating that both compounds exhibit stability and are conducive to experimental synthesis. The semiconducting nature of perovskites is manifested through an energy gap, with values of 1.11 eV at (L–X) for K2TlGaI6 and 1.2 eV at (L–L) for K2RbGaI6, which is also reflected from density of states. Both perovskites display ductile characteristics, but the hardness factor indicates greater strength for K2RbGaI6. The Kleinman parameter value for K2RbGaI6 and K2TlGaI6 indicates a prevalence of bond stretching. The Debye and melting temperatures of K2RbGaI6 surpass that of K2TlGaI6. The assessment of optical response involves examining various parameters that reveal absorption in both the visible and UV regions. The thermoelectric response is gauged by examining prominent values in electrical conductivity, Seebeck, and ZT parameters at high elevated temperatures. The collective findings favor the utilization of K2BGaI6 (B = Tl, Rb) perovskites in environmentally friendly technologies. [ABSTRACT FROM AUTHOR]