Non-ionic surfactant-novel agents to realize high efficiency non-fullerene opaque and semitransparent organic solar cells with Enhanced Stability

The strategy for introducing agents into active layer has been studied as an effective and simple method for optimizing the film morphology and enhancing the performance of organic solar cells (OSCs). Whereas very few agents can be efficient used and make contribution in non-fullerene OSCs. In this work, two novel non-ionic surfactants 1, 8-Octanediol (ODO) and 1, 10-Decanediol (DDO) were introduced to realize high efficiency opaque and semitransparent non-fullerene OSCs for the first time. Doped with an appropriate amount of ODO and DDO in PTB7-Th: ITIC system, highly efficient opaque solar cells have been achieved with a power conversion efficiencies (PCE) of 10.28% and 9.59%, respectively, which exhibited a huge improvement compared with reference cells (PCE of 7.84%). A performance increase is owing to the improvements in short-circuit current density (J(SC)) and fill factor (FF) via the optimization of the film morphology and the enhanced crystallinity of polymer after adding the surfactant. By using a transparent electrode, the semitransparent OSC shows PCE of 7.74% with high average visible transmittance (AVT) of 21.35%. Moreover, both the stability and efficiency of the OSCs were obviously enhanced by adding the surfactants of ODO and DDO compared with the traditional solvent additives (DIO, CN). Our work clearly expressed that add small amount of non-ionic surfactants could be a simple and efficient strategy to improve the performance of the OSCs.