Conjugated Polymer Semiconductors Enabled Multifunctional Interfacial Engineering for High-Performance Inverted...

The interfacial defect challenge between perovskite and electron transport layer (ETL) in inverted perovskite solar cells have become a critical bottleneck for achieving concurrent high efficiency and stability in the process of industrialization. We developed a novel multifunctional integrated polymer semiconductor material P4N-Cl as an interface interlayer between perovskite and [6,6]-phenyl-C₆₁-butyric acid methyl ester. Various functional groups including carbonyl group, Cl atom and sp²-N atom in the polymer backbone effectively passivate defects at the perovskite interface through a synergistic coordination mechanism and significantly suppress non-radiative recombination losses. Simultaneously, the robust interfacial binding at the heterointerface further optimizes the energy level alignment at the perovskite/ETL interface and enhances charge carrier dynamics. The inverted PSCs based on the P4N-Cl multifunctional layer achieved a champion efficiency of 26.20% and a high open-circuit voltage of 1.21 V. The target devices retained 96.2% and 90.2% of their initial power conversion efficiency after 2016 h aging in ambient air (40%-60% relative humidity) and 1500 h maximum power point tracking at 65°C under 1-sun illumination in nitrogen, respectively. This "one-stop" design provides exciting research prospects for constructing a new generation of commercially viable perovskite solar cells with high efficiency and long-term operation stability of devices.