Empowering rubidium-based halide PSCs: A deep dive into ETL material performance

This study uses the SCAPS-1D simulation system to investigate the feasibility of different ETL (Electron Transport Layer) candidates in rubidium-based halide perovskite solar cells (RbGeBr₃). Various ETLs, including TiO₂, SnO₂, IGZO, WS₂, SnS₂ and ZnMgO, are evaluated in terms of their effect on the energy band alignment, charge transport properties, and efficiency metrics. Simulation results indicate that WS₂ exhibits the highest performance with an efficiency of 33.43 %, followed by SnO₂ (32.7 %), ZnMgO (32.5 %), TiO2 (31.74 %), IGZO (29.58 %) and SnS₂ (27.17 %). The superior performance of WS₂ is attributed to its excellent electron mobility (∼100 cm²/Vs) and low conduction band offset, which enhances charge extraction and reduces recombination losses. The results demonstrate that WS₂ is the most promising ETL for Rb–PSCs, offering superior efficiency and charge transport characteristics. Further, the study expands to obtain the performance parameters w.r.t to thickness, defect density, temperature etc to validate the selected ETL material. This offers significant details regarding how ETLs are contributing to boosting the stability as well as efficiency of rubidium-based PSCs, contributing to the advancement of next-generation perovskite photovoltaics.