Analysis of direct band gap A2ScInI6 (A=Rb, Cs) double perovskite halides using DFT approach for renewable energy devices

Abstract

Double perovskite halides are probable renewable energy generation materials that are believed to fulfill the requirements for solving energy scarcity problems. Therefore, investigations of these hallides have emerging applications in the field of optoelectronic and thermoelectric devices. In current work, we also explored the physical characteristics of A2ScInI6 (A = Rb, Cs) double perovskite halides in terms of DFT calculations based all electrons FP-LAPW + lo method for the applications renewable energy devices. The computed enthalpy of formation and goldsmith's tolerance factor shows that studied halides thermodynamically and structurally stable in cubic phase. Further, the investigated values of the Pugh and Poison ratios show a ductile nature by examining the elastic properties. Furthermore, we calculate bandgaps with and without spin–orbit coupling (SOC) by examining electronic properties. To obtain corrected bandgap values with respect to experimental values, we used modified Becke-Johnson (mBJ + SOC) potentials to calculate the bandgap values of Rb2ScInI6 (Eg = 0.90 eV) and Cs2ScInI6 (Eg = 0.95 eV). Also the optical properties of the studied halides are examined with regard to complex dielectric functions. Our calculated results of the optical parameters clearly indicate the optimal absorption of light in infrared (IR) areas, which represents the capability of these halides for being utilized in optoelectronic devices. The transport characteristics were examined in terms of figure of merit, electrical conductivity, thermal conductivity and Seebeck coefficient. Excitedly our results would be helpful for future experimental investigations to evaluate A2ScInI6 (A = Rb, Cs) for applications related to renewable energy devices.

Keywords

• Double perovskite halides
• DFT calculations
• Born stability criteria
• Small direct bandgap
• Seebeck co-efficient