All-Green Solvent and Additive Combination Enables Efficient Nonfullerene Organic Solar Cells via Sequential Deposition Strategy

The performance of organic solar cells mainly depends on the morphology of the active layer. Traditional solution-processed active layers have poor performance due to the random distribution of donor and acceptor materials during solution processing. In addition, halogenated solvents and additives widely used in traditional fabrication processes will have a huge impact on human health and the environment. Herein, an all-green solvent and additive combination strategy is proposed to assist the morphology control of the active layer with sequential deposition (SD) technique. Ultimately, with adopting benzyl viologen (BV) additive as well as ethyl alcohol treatment, PM6:Y6-2BrO-based devices yield a power conversion efficiency of 14.3%, higher than those of the control device (13.24%) and the device solely with BV additives (13.62%). The result demonstrates the feasibility of SD technique to finely control the morphology of active layer in future all-green industrial production.

Automated summary

The performance of organic solar cells is determined by the morphology of the active layer. Traditional solution-based methods have poor performance due to the random distribution of materials. Moreover, the solvents and additives used in traditional fabrication processes have negative effects on human health and the environment. In this study, a strategy using all-green solvent and additive combination with sequential deposition (SD) technique was proposed to control the morphology of the active layer. The results showed higher power conversion efficiency of devices fabricated using this strategy compared to control devices.