ZnPc/CsPbBr3 QDs collaborative interface modification to improve the performance of CsPbBr3 perovskite solar cells

Carbon-based, all-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted considerable interests because of their superior environmental stability, simple and low-cost fabrication process. However, the large energy barrier and high defect states at the CsPbBr3/Carbon interface will cause poor carrier extraction and serious carrier recombination, which further degrade performance of final devices. In this work, we introduce zinc phthalo-cyanine (ZnPc), CsPbBr3 quantum dots (QDs), and ZnPc mixed CsPbBr3 QDs in proper proportion as the CsPbBr3/ carbon interface modification layers of CsPbBr3 PSCs. It is found that the modification layers, especially the ZnPc mixed CsPbBr3 QDs modification layer, can passivate trap states, improve interface contact and optimize energy level alignment at the CsPbBr3/carbon interface, which can further enhance carrier extraction, suppress carrier recombination and improve performance of final devices. By virtue of ZnPc mixed CsPbBr3 QDs modification, a highest efficiency of 10.20% and long-term stability over 6 months has been achieved.