Performance Optimization of CsPb(I1–xBrx)3 Inorganic Perovskite Solar Cells with Gradient Bandgap

In recent years, inorganic perovskite solar cells (PSCs) based on CsPbI3 have made significant progress in stability compared to hybrid organic–inorganic PSCs by substituting the volatile organic component with Cs cations. However, cubic structure of α-CsPbI3 changes orthorhombic non-perovskite phase at room temperature resulting efficiency degradation. The partial substitution an I ion Br benefits for stability. Unfortunately, would enlarge bandgap reducing absorption spectrum range. To optimize balance between band gap and stability, introducing optimizing spatial gradation configuration is effective method broaden light benefit As CsPb(I1–xBrx)3 layer can be adjusted I-Br composition engineering, performance three different variation doping profiles were investigated. effects uniform gradient results show that (Eg) electron affinity(χ) attributed appropriate energy offset, most important performance. With a positive conduction offset (CBO) 0.2 eV translate (ETL)/perovskite interface, valence (VBO) 0.24 hole (HTL)/perovskite highest power conversion (PCE) 22.90% open–circuit voltage (VOC) 1.39 V, short–circuit current (JSC) 20.22 mA/cm2 filling factor (FF) 81.61% was obtained x = 0.09. By carrying out further optimization configuration, evaluation single back directed towards contact, optimized (front interface CBO 0.18 eV, VBO 0.15 eV) obtained, increasing 23.03%. Finally, double evaluated. PCE 23.18% VOC close 1.44 JSC 19.37 FF 83.31% obtained.