Multifunctional Ternary Oxide for Efficient CsPbBr3 Perovskite Solar Cells on Rigid and Flexible Substrate via All-Low-Temperature Process

Efficient CsPbBr3 perovskite films and the low-temperature fabrication of electron transport layers (ETLs) are crucial for the commercial viability of CsPbBr3 perovskite solar cells (PSCs). We present a vapor-assisted solution technique that produces high-quality CsPbBr3 perovskite films without annealing. Doping ZnO with trivalent metals such as yttrium (Y), antimony (Sb), and iron (Fe) improves the electrical properties and energy alignment with CsPbBr3. Our experiments show that Sb doping enhances charge extraction and reduces interface carrier recombination to achieve a power conversion efficiency (PCE) of 9.55% in the inorganic CsPbBr3 PSCs. The optimized device maintains over 90% of its original PCE after 90 days under 65% relative humidity and 65 °C. Additionally, flexible CsPbBr3 PSCs with an Sb-ZnO ETL achieve a record 6.06% efficiency with remarkable mechanical durability to retain 91.8% of initial PCE after 1000 bending cycles at a 3 mm curvature radius.