Design and optimization of (FA)2BiCuI6-based double perovskite solar cells using kesterite CBTS as hole transport layer for high power conversion and quantum efficiency

Abstract This work introduces the design of a novel architecture for double perovskite solar cells (DPSCs) utilizing (FA) 2 BiCuI 6 , known for its enhanced stability relative to single perovskite materials for production of efficient, ultra-thin solar cells. The proposed architecture features a unique device configuration of ITO/WO 3 /(FA) 2 BiCuI 6 /Cu 2 BaSnS 4 /W, incorporating a Kesterite type Cu-based quaternary chalcogenide material, Cu 2 BaSnS 4 known as CBTS, is used as hole transport layer (HTL) with a bandgap of 1.9 eV, WO 3 as the electron transport layer (ETL) with a 2.6 eV bandgap, and (FA) 2 BiCuI 6 as the absorber layer with a 1.55 eV bandgap. The study provides an in-depth theoretical analysis of the energy band structure, defects, and quantum efficiency of the DPSC, highlighting the device’s post-optimization photovoltaic parameters. Remarkably, the optimized DPSC demonstrated superior performance with a PCE of 24.63%, V oc of 1.16 V, J sc of 25.67 mA cm −2 , and FF of 82.87%. The research also explores the effects of various factors on photovoltaic performance, including temperature, interface defect, and generation and recombination rates, as well as work function of back contact materials. The results underscore the exceptional potential of (FA) 2 BiCuI 6 , especially when combined with the HTL CBTS, in significantly reducing sheet resistance and enhancing the overall performance of solar cells. The design is validated using the SCAPS-1D simulation software tool.