Improved Performance of Organic Solar Cells by Utilizing Green Non‐halogen Additive to Modulate Active Layer Morphology

Using solvent additives to optimize the morphology of the blend films in organic solar cells (OSCs) is a simple and effective method. Here, methyl salicylate (MeSA) is used as a non-halogen additive for inverted OSCs, and the impact of this additive on the blend film and photovoltaic performance is carefully investigated. The significant increase in short-circuit current density (J(SC)) and fill factor (FF) leads to a significant improvement in device performance, which is caused by bicontinuous interpenetrating phase separation and balanced charge transport. The results indicate that MeSA modulates the phase distribution and promotes the accumulation of ordered molecules in the blend film, thus exhibiting an efficiency of 9.45% and improved FF (>70%) with a 7% MeSA additive. Most importantly, MeSA can be added in large doses (7%) compared to other traditional solvent additives (e.g., 1,8-diiodooctane, 1-chloronaphthalene, etc.), indicating that its concentration variation has little effect on performance and is conducive to repeatable, large-scale production, which is of great importance for industrialization.