CsPbBr3 Quantum Dots‐Sensitized Mesoporous TiO2 Electron Transport Layers for High‐Efficiency Perovskite Solar Cells

The carrier transport layer plays a critical role in high efficiency and stable perovskite solar cells (PSCs). Herein, CsPbBr 3 quantum dots‐sensitized mesoporous TiO 2 (CPB–TiO 2 ) electron transport layer for fabricating high‐quality perovskite films with enhanced phase stability is developed. The CPB–TiO 2 layer enhances the perovskite crystallinity, phase stability, and reduces the nonradiative carrier recombination in PSCs. As a result, the CPB–TiO 2 significantly improves the power conversion efficiency of FAPbI 3 PSCs from 23.11% to 24.46% and reduces the device hysteresis. The CPB–TiO 2 –FAPbI 3 device shows enhanced stability, retaining 90% of its initial efficiency after 500 h operation at maximum power point tracking under 1 sun illumination, whereas the control device degrades to 80% of initial performance in the first 200 h. In addition, this strategy is applicable to CsPbI 3 perovskite, which provides a new and general strategy for preparing high‐efficiency PSCs.