Multifunctional\nTernary Oxide for Efficient CsPbBr<sub>3</sub> Perovskite Solar Cells\non Rigid and Flexible Substrate via\nAll-Low-Temperature Process

Efficient CsPbBr<sub>3</sub> perovskite films and the\nlow-temperature\nfabrication of electron transport layers (ETLs) are crucial for the\ncommercial viability of CsPbBr<sub>3</sub> perovskite solar cells\n(PSCs). We present a vapor-assisted solution technique that produces\nhigh-quality CsPbBr<sub>3</sub> perovskite films without annealing.\nDoping ZnO with trivalent metals such as yttrium (Y), antimony (Sb),\nand iron (Fe) improves the electrical properties and energy alignment\nwith CsPbBr<sub>3</sub>. Our experiments show that Sb doping enhances\ncharge extraction and reduces interface carrier recombination to achieve\na power conversion efficiency (PCE) of 9.55% in the inorganic CsPbBr<sub>3</sub> PSCs. The optimized device maintains over 90% of its original\nPCE after 90 days under 65% relative humidity and 65 °C. Additionally,\nflexible CsPbBr<sub>3</sub> PSCs with an Sb-ZnO ETL achieve a record\n6.06% efficiency with remarkable mechanical durability to retain 91.8%\nof initial PCE after 1000 bending cycles at a 3 mm curvature radius.