Optimization of efficiency of CsPbI2Br by using different electron transport and hole transport layers: A DFT and SCAPS-1D simulation

Abstract

In this article, we embark on an exciting journey to identify the ideal electron transport layers (ETL) and hole transport layers (HTL) that can significantly boost the efficiency of CsPbI₂Br-based solar cells. Utilizing first-principles calculations with the modified Becke-Johnson potential (mBJ) and spin-orbit correction, we uncovered the direct band gap property of CsPbI₂Br, measuring an impressive 1.81 eV. Coupled with its remarkable absorption coefficient of 10⁵ cm⁻¹ and minimal reflectivity throughout the visible spectrum, this material stands out as an emerging absorber layer for photovoltaic cells. Also, using cutting-edge SCAPS-1D simulations, we explore a range of ETL materials, including TiO₂, ZnO, CdS, STO, WS₂, and Nb₂O₅, alongside HTL options like NiO, Spiro, SnS, CuI, Cu₂O, and CuSbS₂. Our findings reveal that Nb₂O₅ and Cu₂O emerge as the most promising candidates for ETL and HTL to enhance the performance of CsPbI₂Br absorbers, opening the door to more efficient solar energy solutions. The efficiencies achieved with the ETL and HTL-based solar cells, specifically Au/CsPbI₂Br/Nb₂O₅/FTO and Au/Cu₂O/CsPbI₂Br/FTO, are impressive, standing at 17.91 % and 18.13 %, respectively. Moreover, various factors such as the thickness of the absorbing layer, HTL, and ETL, along with total defect density (N_t), donor and acceptor defect densities of both the absorber and the transport layers, and the device temperature, significantly influence the performance metrics of the Au/Cu₂O/CsPbI₂Br/Nb₂O₅/FTO solar cell. Our findings reveal impressive values: a maximum open-circuit voltage (V_oc) of 1.21 V, a short-circuit current (J_sc) of 32.47 mA/cm², a fill factor of 87.7 %, and an efficiency (η) of 22.31 %. These findings exceed the previously reported values for halide perovskite based solar cells, underscoring the promise of this research in shaping the future of cutting-edge perovskite-based solar cells.