Optoelectronic properties and solar cell performance of lead free halide perovskites for energy harvesting application

Compared to conventional silicon solar cells, perovskite solar cells (PSCs) provide a number of advantages, including a high power conversion efficiency (PCE) and affordable manufacturing expenses. Lead poisoning and stability concerns have been the main challenge to use lead halide perovskites as absorber layers in perovskite solar cells. These obstacles have made it much more difficult to industrialize this state-of-the-art technology. Researchers are now focusing on lead-free metal halide perovskites due to the negative impacts of lead in perovskite solar cells. In demand to explore the physical properties and efficiency of perovskites, as well as their working principle, a comprehensive study of both the material and device is required. Therefore the WEIN2k and SCAPS-1D tools are employed to explore the structural, electronic and optical properties along with the solar cell efficiency of halide Cs2TMGaCl6 (TM = Cu, Ag) perovskites. The reported findings of structural properties are aligned with experiments. The electronic properties of Cs2TMGaCl6 (TM = Cu, Ag) compounds reveal the direct bandgap and visible light semiconducting nature make them ideal for optoelectronic devices and solar cell applications. To model the efficiency of these compounds based solar cells, WS2 and TiO2-SnO2 as electron transport layer (ETL), different type of hole transport layer (HTL) and Cs2TMGaCl6 (TM = Cu, Ag) as the absorber layer is used. The most efficient solar cell is the FTO/WS2/Cs2TMGaCl6 (TM = Cu, Ag)/CBTS/Cu, which achieved Jsc values of 15.32 and 12.30 mA cm-2, Voc values of 1.44 and 1.13 V, FF values of 81.08 and 79.39%, and PCE values of 14.14 and 14.08% respectively upon consequence of radiative recombination coefficients. This finding facilitates future studies aimed at developing fully inorganic perovskite photovoltaics lacking of lead halide, demonstrating improved photovoltaic performance.