Alcohol-dispersed polymer complex as an effective and durable interface modifier for n-i-p perovskite solar cells

Abundant interfacial defects remain a significant challenge that hampers both the efficiency and stability of perovskite solar cells (PSCs). Herein, an alcohol-dispersed conducting polymer complex, denoted as PEDOT:F (Poly (3,4-ethylene dioxythiophene):Perfluorinated sulfonic acid ionomers), is introduced into the interface between perovskite and hole transporting layer in regular-structured PSCs. PEDOT:F serves as a multi-functional interface layer (filling grain boundaries and covering perovskite’s grain-surface) to achieve a robust interaction with organic groups within perovskites, which could induce a structural transformation of PEDOT to increase its conductivity for the efficient hole-transport. Furthermore, the strong interaction between PEDOT and perovskites could promote an effective coupling of undercoordinated Pb2+ ions with the lone electron pairs near O & S atoms in PEDOT molecules, thereby enhancing defect passivation. Additionally, PEDOT:F with inherent hydrophobic properties prevents effectively moisture invasion into perovskites for the improved long-term stability of the PSCs. Consequently, the PEDOT:F-based PSCs achieved a champion efficiency of 24.81%, and maintained ca. 92% of their initial efficiency after 7680 h of storage in a dry air environment, accompanied by the enhanced photothermal stability.