Polymer‐Regulated SnO2 Composites Electron Transport Layer for High‐Efficiency n–i–p Perovskite Solar Cells

Abstract

SnO2 electron transport layer (ETL) plays a critical role in constructing a planar perovskite solar device. Improving SnO2 ETL properties and understanding of interfacial energy loss are key factors to fabricate highly efficient and reproducible perovskite solar cells (PSCs). Herein, a nonionic surfactant, polyethylene oxide‐polypropylene oxide‐polyethylene oxide (P123), is introduced to suppress the aggregation of SnO2 nanoparticles for a uniform SnO2 ETL. The P123 polymer can maintain the SnO2 colloidal size around 10 nm over 72 h at 35 °C and thus promote the dispersion of nanoparticles in SnO2 precursor. By spin coating P123‐doped SnO2 (SnO2‐P) colloid, the compactness and uniformity of SnO2 layer are improved significantly. Correspondingly, SnO2‐P‐based devices demonstrate a champion efficiency with enhanced open‐circuit voltage (V OC) of 1.162 V. Due to the SnO2/perovskite interface binding interaction, the devices gain a high long‐term stability, retaining 85% of their initial performance after 1000 h storage in air. Equally important, the polymer‐regulated ETL allows a competitive efficiency of 17.44% with active area of 1.00 cm2, exhibiting much potential for large‐scale solar devices. This ETL modification approach provides a new and simple route to improve the quality of SnO2 colloid solution for fabricating efficient perovskite devices.