Engineering Next-Generation Rb<sub>2</sub>SeI<sub>6</sub> Perovskite Solar Cells for Sustainable Energy Development
Md. Tarekuzzaman, Khandoker Isfaque Ferdous Utsho
Abstract
Halide perovskites have emerged as promising candidates for next-generation photovoltaics due to their exceptional light-harvesting capabilities, cost-effectiveness, and compatibility with lightweight designs. This study investigates the potential of Rb 2 SeI 6 as an absorber layer in high-efficiency hybrid perovskite solar cells (HPSCs), integrating four electron transport layers (ETLs), namely, IGTO, SnS 2, C 60, and CeO 2, and a diverse array of hole transport layers (HTLs), such as MoO 3, CBTS, CuI, P3HT, PEDOT:PSS, PTAA, CuSbS 2 GaAs, C 6 TBTAPH 2, and CFTS. Through SCAPS-1D simulations, MoO 3 was identified as the optimal HTL, and thorough optimization of layer thicknesses, doping concentrations, and defect densities (including interfaces) across the absorber, ETL, and HTL was conducted. Four device architectures were evaluated: Device I (ITO/IGTO/Rb 2 SeI 6 /MoO 3 /Ni), Device II (ITO/SnS 2 /Rb 2 SeI 6 /MoO 3 /Ni), Device III (ITO/C 60 /Rb 2 SeI 6 /MoO 3 /Ni), and Device IV (ITO/CeO 2 /Rb 2 SeI 6 /MoO 3 /Ni). Among four device architectures, Device I (ITO/IGTO/Rb 2 SeI 6 /MoO 3 /Ni) achieved the highest performance with a PCE of 31.80%, V OC of 1.02 V, J SC of 37.22 mA/cm 2, and FF of 83.63%. The optimized absorber thickness, acceptor density, and defect density were 1 μm, 1 × 10 15 cm –3, and 1 × 10 14 cm –3, respectively. Comprehensive analyses of band alignment (VBO/CBO), quantum efficiency, carrier recombination dynamics, and impedance analysis highlighted the device’s operational stability and efficiency. Additional evaluations of J – V characteristics, capacitance behavior and Mott–Schottky characteristics, shunt and series resistances, and back contact effects further validated the robustness of the optimized structure. This work demonstrates the significant potential of Rb 2 SeI 6 for lead-free solar cells, providing optimized structural parameters and in-depth performance insights.