Efficient Perovskite Solar Cells And Perovskite/Sillicon Tandem Solar Cells Using The Coordinated Passivation Strategy

Perovskite/silicon tandem solar cells have been developed rapidly in recent years.A semitransparent perovskite top cell with excellent photovoltaic performance is one of the key factors to achieve efficient and stable four-terminal tandem solar cells.Generally,defects tend to generate at grain boundaries and film surfaces during the preparation of perovskite films.Passivation have been considered as an effective way to improve the performance of perovskite solar cells(PSCs)by passivating the defects.But most previously studies were focused on single defect passivation.In this study,surface modification and internal doping were used to passivate both grain boundary and surface defects simultaneously.It was shown that a thin two-dimensional(2D)structure was formed on the surface of perovskite films by the coating of iodiphenylamine(PEAI),which passivated the surface defects and improved the stability of perovskite films.The doping of Na F into perovskite precursor solution changed the nucleation process of crystals to make the grains larger as well as enhance the conductivity at the grain boundary.The fluorescence lifetime of the co-passivated film was prolonged and the carrier recombination rate of the co-passivated film was slowed down as compared with the control film.The thermal stability of the co-passivated film was better than that of the original film after heating at 85°C in nitrogen for 100 h.As a result,the efficiency of the co-passivated device increased from 16.54% to 20.59%,maintaining 87.3% of its initial efficiency after 1000 h in nitrogen.Furthermore,based on the cooperative passivation strategy,we replaced the metal electrode with transparent ITO electrode.The PCE of the optimized semitransparent PSCs reached to 17.58%.Combining the semitransparent PSCs with silicon heterojunction solar cells(SHJ),the efficiency of the four-terminal p-i-n perovskite/silicon tandem solar cells reached to23.83%.