DFT and SCAPS-1D assisted investigation of optoelectronic, thermoelectric, and optimized photovoltaic performance of halide double perovskite K2LiInI6.

Halide perovskite-based photovoltaics have urged a significant research community to investigate photovoltaic features due to their exceptional stability, optimal energy gap, and optical response. This study emphasizes the scrutiny of structural, mechanical, stability, and opto-electronic aspects of K2LiInI6 by using the DFT-oriented Wien2k code to utilize as an absorber material in solar cells. The structural aspects confirm cubic phase configuration and formation energy value (-2.35 eV/atom), and ab initio molecular dynamics (AIMD) simulation validates thermal robustness and stability of K2LiInI6. The mechanical attributes are illustrated thoroughly, which confirm the ductility, mechanical stability, and anisotropic response of K2LiInI6. The optoelectronic features validate direct Eg of 1.50 eV, high absorption (7.95 × 104/cm), lower reflectivity (0.12), and optical loss in the visible photo spectrum. Thermal transport features of K2LiInI6 are determined to evaluate the figure of merit, which is found to be 0.74 at ambient temperature, ensuring the thermal energy harvesting potential. The solar cell device simulation, ITO/ETL(CSTO/PEIE/ZnS)/K2LiInI6/HTL (SrCu2O2), is achieved by using SCAPS-1D simulation. The effect of optimization of device parameters, such as absorber thickness and operational temperature, on the photovoltaic (PV) performance is also investigated. Among the explored device structures, optimized configuration ITO/CSTO/K2LiInI6/SrCu2O2 reveals the conversion efficiency of 30%, which is the highest among the studied configurations. Hence, the findings on thermoelectric and photovoltaic performance discussed in the present investigation will be significantly beneficial in the enhancement of the effectiveness of thermoelectric devices and perovskite solar cells.