Enhanced Resonance for Facilitated Modulation of Large‐Area Perovskite Films with Stable Photovoltaics

Abstract Upscaling efficient and stable perovskite films is a challenging task in the industrialization of perovskite solar cells partly due to the lack of high‐performance hole transport materials (HTMs), which can simultaneously promote hole transport and regulate the quality of perovskite films especially in inverted solar cells. Here, a novel HTM based on N–C = O resonance structure is designed for facilitating the modulation of the crystallization and bottom‐surface defects of perovskite films. Benefiting from the resonance interconversion (N–C = O and N + = C–O − ) in donor‐resonance‐donor (D‐r‐D) architecture and interactions with uncoordinated Pb 2+ in perovskite, the resulting D‐r‐D HTM with two donor units exhibits not only excellent hole extraction and transport capacities, but also efficient crystallization modulation of perovskite for high‐quality photovoltaic films in large area. The D‐r‐D HTM‐based large‐area (1.02 cm 2 ) devices exhibit high power conversion efficiencies (PCEs) up to 21.0%. Moreover, the large‐area devices have excellent photo‐thermal stability, showing only a 2.6% reduction in PCE under continuous AM 1.5G light illumination at elevated temperature (≈65 °C) for over 1320 h without encapsulation.