Tailoring Functionalized Dipole Molecules for Enhanced Efficiency and Stability of Perovskite Solar Cells.

Dipole interlayer molecules have been incorporated into perovskite solar cells (PSCs) to enhance the energy level alignment between the perovskite and charge transport layers, improving charge extraction and device performance. However, the conventional dipole interlayer with a singular functionality is inadequate for high-efficiency PSCs with excellent long-term stability. Here, we design a functionalized dipole interlayer (FDI) between perovskite and electron transport layers that integrates multiple functionalities onto a novel dipole molecule. The FDI not only realizes the field-effect function of the conventional dipole interlayer for tuning energy level matching but also extends the function of the dipole interlayer for diminishing defects, fortifying the perovskite's resistance to moisture, and impeding the migration of I^- ions within the perovskite layer across perovskite interface. Consequently, FDI proves to be beneficial to air-processed PSCs under a high relative humidity of 45%, yielding enhanced power conversion efficiencies from 19.44 to 21.13%. Furthermore, unencapsulated devices exhibit excellent humidity stability and thermal stability under the standardized International Summit on Organic Photovoltaic Stability (ISOS) protocols for over 1000 h (ISOS-D-1) and 700 h (ISOS-D-2I), respectively. This work extends new functions for dipole interlayers and offers a convenient and effective approach for enhancing the performance of PSCs prepared in air environments.