Achieving 12.6% Efficiency in Single‐Component Organic Solar Cells Processed from Nonhalogenated Solvents

Single‐component organic solar cells (SCOSCs), which contain only one photoactive material in their active layers, promise many advantages with respect to the excellent device and morphological stabilities and a simplified film fabrication process. However, most of the high‐efficiency SCOSCs are fabricated by halogenated solvents. Herein, the eco‐friendly and highly efficient SCOSCs based on a conjugated block copolymer PBDB‐T‐ b ‐PYT with power conversion efficiencies (PCEs) of over 12% are developed by utilizing a series of halogen‐free processing solvents (including tetrahydrofuran, toluene, o ‐xylene), being higher than those of the devices cast from halogenated solvents (including chloroform, chlorobenzene, 1,2‐dichlorobenzene). Impressively, by using o ‐xylene as processing solvent for the PBDB‐T‐ b ‐PYT active layer, high and balanced charge transport properties, and well‐developed morphological features are observed, leading to a high PCE of 12.60%, which is the highest value among SCOSCs to date. Importantly, the non‐halogenated solvents‐processed devices exhibited better storage and operational stabilities as compared to the chloroform (CF)‐processed SCOSCs. More importantly, higher photovoltaic performance (over 12% PCEs) of the green‐solvent‐processed devices as compared with the CF‐processed devices fabricated by blade coating in ambient conditions are achieved, suggesting the promising prospects of SCOSCs toward industrial production, particularly being relevant for environmentally benign solvents.