Eco‐friendly solution processing of all‐polymer solar cells: Recent advances and future perspective

All‐polymer solar cells (all‐PSCs) exhibit great potentials in commercial applications. All‐PSCs have observed steady performance gains with power conversion efficiency now reaching over 17% in the open literature. However, the current processing of all‐PSCs relies predominantly on toxic, chlorinated solvents in moisture‐free environments, representing a significant barrier for their commercialization due to the added costs to handle and dispose of such solvents. There is thus an urgent need for safe, environmentally benign, and sustainable ink‐based processing methods to produce all‐PSC devices reliably and reproducibly in ambient air. In this perspective, fundamental insights on the interplay between all‐polymer blend morphologies and eco‐friendly solvents are provided. Also, we discuss the recent successes of the green processing methods to manipulate the photoactive morphologies for high‐efficiency all‐PSCs. In the end, we provide an outlook on future challenges and opportunities of eco‐friendly solvents processed all‐PSCs for large‐scale manufacturing.