P3 Nanosecond Laser Patterning of Perovskite Solar Cells: Defect Passivation Through Formation of PbI2 and Br-rich Interface Layers

P3 patterning with ns and ps laser pulses for monolithic series interconnection of perovskite solar cells was systematically investigated. The use of ns laser pulses generates a larger amount of PbI2 and a Br-rich interface layer in the processed area, which proved to be beneficial for P3 patterning due to improved defect passivation. Thus, the P3 step should be carried out with ns laser pulses for an optimized separation of adjacent cells, while ps laser pulses were recommended for the P2 interconnect. Accordingly, suitable laser parameters for optimal laser patterning are demonstrated and novel insights into the controversial issue about the influence of PbI2 on the overall photovoltaic performance of perovskite solar cells are presented.