Evaporation‐Free Organic Solar Cells with High Efficiency Enabled by Dry and Nonimmersive Sintering Strategy

Abstract

A solution-processed top electrode is critical to unlock the full potential of all-solution-processed organic solar cells (OSCs) for practical applications. However, the enabled devices suffer from low efficiency (<12%) mainly because of the irreversible damages induced by the top-electrode deposition process. Herein, a strategy of dry and nonimmersive sintering is demonstrated by introducing a hydrogen-intercalated molybdenum oxide layer to sinter isolated Ag nanoparticles into the top electrode (all from solution process) with little influences/issues on underlying device structures. Fundamentally, it is unveiled that the intercalated hydrogen will bond with the amino group of the ligands around Ag nanoparticles, which promotes the exposed nanoparticles to merge along a certain crystal orientation (≈45°) and form a conductive electrode (8.6 Ω sq−1). Importantly, the sintered electrode offers 70% optical reflection in the 700–1050 nm wavelength region, which is essential to enhance the light absorption of high-performance nonfullerene acceptors. Consequently, a record efficiency of 15% is achieved, driving all-solution processed OSCs toward commercial applications.