First-principle investigation of thermoelectric and optoelectronic properties of Rb2KScI6 and Cs2KScI6 double perovskite for solar cell devices

Abstract

Double perovskite (DP) halides are a reliable source of renewable energy that plays a vital role to fulfill the requirements of energy crunch. Therefore, the analysis of these perovskite halides have promising uses for thermoelectric and optoelectronics purposes. We investigated the thermoelectric and optoelectronics properties of Rb2KScI6 and Cs2KScI6 halides for use in renewable energy devices by using FP-LAPW + lo approach based on DFT. The calculated Goldsmith's tolerance factor and enthalpy of the formation of studied halides reveal that these are structurally and thermodynamically stable in cubic phase. Moreover, the analyzed value of Poisson and Pugh ratio reveals ductile nature of these materials. Further, we computed the bandgaps by analyzing electronic characteristics. For bandgap calculations of Rb2KScI6 (Eg = 2.75 eV) and Cs2KScI6 (Eg = 2.65 eV), we employed mBJ potentials to obtain precise values as comparison to experimental values. The complex dielectric function used to reveal the optical properties of the analyzed materials. The calculated optical results clearly show the maximum absorption of light in infrared (IR) region revealed that the analyzed materials are appropriate for optoelectronic purposes. The thermoelectric behavior was examined as to figure of merit (ZT), electrical-conductivity (EC), the Seebeck-coefficient (S) as well as thermal-conductivity. Animatedly in future, the analyzed consequences would be supportive to experimental investigation of Rb2KScI6 and Cs2KScI6 for renewable energy device applications.

Keywords

• First-principle investigation
• Born stability requirements
• Direct bandgap
• Seebeck co-efficient
• Figure of merit (ZT)