Improved Current Density and Fill Factor of Non‐Fullerene Organic Solar Cells Prepared under Solvent Vapor Atmosphere

Abstract

With the continuously increasing power conversion efficiency (PCE) in recent years, organic solar cells (OSCs) have attracted extensive attention as a new clean energy. Further improving PCE is an inevitable requirement for the OSC for commercialization. Herein, PM6: Y6‐based non‐fullerene organic solar cells are prepared by spin‐coating active layer under methanol vapor atmosphere, methanol vapor regulates the active layer morphology and optimizes the molecular arrangement during the active layer film‐forming process, and enriches the acceptor material Y6 on the active layer surface, improving the contact interface between active layer and cathode buffer layer. The improved active layer morphology and interface contact facilitates charge transport and extraction, boosts short‐circuit current density and fill factor, and results in a better PCE of 17.59%, while the PCE of the control device without methanol vapor atmosphere is 16.37%. The results suggest that preparing an active layer under a solvent vapor atmosphere is a simple and efficient method to optimize the active layer morphology and improve the performance of organic solar cells, and this method is convenient to be extended to prepare large‐area and high‐efficiency organic photovoltaic devices.