Completely Fused Non‐Fullerene Acceptor Enables Efficient Postprocessing‐Free Organic Photovoltaics Cells

Abstract The photovoltaic performance of organic photovoltaic (OPV) cells can be significantly improved by regulating the aggregation structure and film formation kinetics of the constituent materials. However, many regulation strategies, including the use of additives and annealing, require complex fabrication processes and additional investments, which poses challenges for the industrialization of OPV cells. In this work, a completely fused non‐fullerene acceptor, GS‐20 is designed and synthesized, with strong aggregation properties. The incorporation of GS‐20 as a third component into the PBQx‐TF:eC9‐2Cl‐based cell accelerates aggregation of eC9‐2Cl and improves molecular stacking by promoting film deposition. The as‐cast ternary OPV cells fabricated without any post‐treatments exhibited a high V OC of 0.890 V and a maximum PCE of 19.0%. Moreover, a postprocessing‐free OPV module is fabricated using the blade coating method and obtains a satisfactory PCE of 13.5%, indicating excellent feasibility for large‐scale preparation. This work realizes an efficient postprocessing‐free OPV cell through molecular design and ternary strategy, facilitating the industrialization of OPV technology.