Dual Ions Passivating FAPbBr3 Perovskite Quantum Dot Films via a Vacuum Drying Method for Stable and Efficient Solar Cells with an Ultrahigh Open-Circuit Voltage of over 1.67 V

Defects located in the surface of quantum dots highly impact carrier dynamics and transfer, which would limit the photoelectric conversion efficiency (PCE) of perovskite quantum dot solar cells. Herein, we deposit high-quality FAPbBr3 quantum dot films through passivating Pb salts and conducting damage-free drying processes. The results indicate that the process of PbBr2 treatment and vacuum drying process fill both the Pb2+ and Br– vacancies and minimize the damage of the FAPbBr3 quantum dot film. The device assembled with this film achieved a champion PCE of 3.11% and involved an ultrahigh open-circuit voltage of 1.67 V or more. In addition, both the corresponding FAPbBr3 quantum dot films and devices exhibited higher humidity stability than the control films and devices. These studies will provide insights for designing high-quality perovskite quantum dot films with superior optoelectronic properties.