Improved efficiency and stability of perovskite solar cells with molecular ameliorating of ZnO nanorod/perovskite interface and Mg-doping ZnO*

Abstract

Despite the advanced efficiency of perovskite solar cells (PSCs), electron transportation is still a pending issue. Here the polymer polyvinylpyrrolidone (PVP) is used to enhance the electron injection, which is thanks to the passivation of the defects at the interface between the ZnO electron transporting layer (ETL) and the perovskite. The application of the PVP layer inhibits the device degradation, and 80% of the primary efficiency is kept after 30 d storage in air condition. Additionally, the efficiency of the device is further enhanced by improving the conductivity and crystallinity of the ZnO ETL via Magnesium (Mg) doping in the ZnO nanorods (ZnO NRs). Moreover, the preparation parameters of the ZnO NRs are optimized. By employing the high-crystallinity ZnO ETL and the PVP layer, the power conversion efficiency (PCE) of the champion device is increased from 16.29% to 19.63%. These results demonstrate the advantages of combining mesoscale manipulation with interface modification and doping together.