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.