Targeted Adjusting Molecular Arrangement in Organic Solar Cells via a Universal Solid Additive

The incorporation of solid additive has been considered as an effective strategy for developing organic photovoltaics with multi‐components, which is independent of dynamics, playing unique roles in morphology adjustment. However, their complex working mechanisms involving specific chemical structures are selective to material systems, hence limiting their university and flexibility in application. Herein, an inert small‐molecular compound naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole (NT) is introduced into the bulk‐heterojunction blend as the solid additive, which can function with various material systems and solvents, depending on its simple π‐conjugated structure and S⋯N interaction for adjusting molecular alignment. It is interesting to note that the introduced NT can not only improve device performance, but also simplify complicated pre‐ or post‐processing methods, reduce impact from batch‐to‐batch differences, construct sufficient energy transfer channel as well as improve device stability. The resulting devices based on PTzBI‐dF:Y6‐BO system show an impressive power conversion efficiency of 17.4% with obviously enhanced T80 lifetime of >1200 h. These findings provide useful guidelines for exploring potential universal solid additives benefitting toward commercial application.