Enhanced resonance for facilitated modulation of large-area perovskite films with stable photovoltaics.

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, we design a novel HTM based on N-C = O resonance structure 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 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 ) 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. This article is protected by copyright. All rights reserved.