Unveiling 2D RbBiICl and RbBiICl perovskites for optoelectronic, solar cell and photocatalytic applications.

The removal of harmful lead from perovskite materials has led to a surge in interest in lead-free perovskite-based solar cells. Using density-functional theory (DFT) and a numerical simulation method using the solar cell capacitance simulator SCAPS-1D. This work aims to advance the field of lead-free perovskite solar cells by conducting a comparative analysis of lead-free perovskite materials. WIEN2k is employed to explore the structural, electronic and optical properties of the two dimensional (2D) halide perovskites RbBiICl and RbBiICl, while their solar cell (SC) efficiency is estimated using SCAPS-1D. The reported structural properties are aligned with the experimental values. The electronic properties of RbBiICl and RbBiICl reveal their direct band gap semiconducting nature with band gaps of 2.02 and 1.99 eV, respectively. Their optical properties reveal that the compounds are activated under visible light, making them ideal for optoelectronic device and SC applications. To model the efficiency of these compound-based solar cells, MoO is optimized as an electron transport layer (ETL); TiO-SnS is optimized as a hole transport layer (HTL), and the respective thickness of the ETL, HTL and absorber are optimized as 180, 150 and 900 nm, respectively. RbBiICl and RbBiICl are used as the absorber layer (AL). Optimized solar cell devices based on FTO/TiO-SnO/RbBiICl and RbBiICl/MoO/Ni achieved short-circuit current densities of 9.02 and 10.11 mA cm, open-circuit voltages of 1.41 and 1.35 V, fill factors of 84.69% and 83.93%, and power conversion efficiencies (PCE) of 11.39% and 11.52%, respectively. Additionally, photocatalytic analysis demonstrates that all of the materials can evolve H from H and O from HO/O. Additionally, the compound under study can reduce CO to produce HCOOH, CO, HCHO, CHOH and CH. Based on these findings, 2D perovskites could be used in optoelectronic devices, photovoltaics, and photocatalysis-especially for water splitting and CO reduction driven by visible light. These results facilitate future studies aimed at developing fully inorganic lead-free perovskite-based photovoltaics and photocatalysts.