Enhanced Stability and Efficiency in Ge–Pb-Based Perovskite Solar Cells through PCCMAI-Induced Ge Defect Passivation

The advantages of the Ge–Pb-based perovskite solar cells (PSCs), such as low bandgap, have made this kind of PSC popular nowadays. Nevertheless, they have adverse properties that need to be fixed, such as short lifetime and fast crystallization process, which causes Ge defects. In this research, the passivation of Ge defects by using pyridinium chlorochromate methylamine iodine (PCCMAI) in the perovskite film (PF) structure is investigated. By using PCCMAI, the PSC's performance enhancement and surface morphology optimization were observed. It is determined that by the reaction of PCCMAI in the perovskite solvent, a coordination polydentate is formed in Ge–Pb mixed perovskite, and it results in the improvement of crystallization quality and electron transfer. After PCCMAI treatment of the Ge–Pb-based perovskite film, the measured power conversion efficiency (PCE) indicates that the performance of the fabricated PSC increased from 16.85% to 20.14%. Moreover, fabricated PSCs show an increment in stability after PCCMAI treatment.