In situ polymerization of water‐induced 1,3‐phenylene diisocyanate for enhanced efficiency and stability of inverted perovskite solar cells

Abstract In the realm of photovoltaics, organometallic hybridized perovskite solar cells (PSCs) stand out as promising contenders for achieving high‐efficiency photoelectric conversion, owing to their remarkable performance attributes. Nevertheless, defects within the perovskite layer, especially at the perovskite grain boundaries and surface, have a substantial impact on both the overall photoelectric performance and long‐term operational stability of PSCs. To mitigate this challenge, we propose a method for water‐induced condensation polymerization of small molecules involving the incorporation of 1,3‐phenylene diisocyanate (1,3‐PDI) into the perovskite film using an antisolvent technique. Subsequent to this step, the introduction of water triggers the polymerization of [P(1,3‐PDI)], thereby facilitating the in situ passivation of uncoordinated lead defects inherent in the perovskite film. This passivation process demonstrates a notable enhancement in both the efficiency and stability of PSCs. This approach has led to the attainment of a noteworthy power conversion efficiency (PCE) of 24.66% in inverted PSCs. Furthermore, based on the P(1,3‐PDI) modification, these devices maintain 90.15% of their initial efficiency after 5000 h of storage under ambient conditions of 25°C and 50 ± 5% relative humidity. Additionally, even after maximum power point tracking for 1000 h, the PSCs modified with P(1,3‐PDI) sustain 82.05% of the initial PCE. Small molecules can rationally manipulate water and turn harm into benefit, providing new directions and methods for improving the efficiency and stability of PSCs.