Polymer Acceptors for High‐Performance All‐Polymer Solar Cells

Abstract All‐polymer solar cells (all‐PSCs) have attracted considerable attention owing to their pronounced advantages of excellent mechanical flexibility/stretchability and greatly enhanced device stability as compared to other types of organic solar cells (OSCs). Thanks to the extensive research efforts dedicated to the development of polymer acceptors, all‐PSCs have achieved remarkable improvement of photovoltaic performance, recently. This review summarizes the recent progress of polymer acceptors based on the key electron‐deficient building blocks, which include bithiophene imide (BTI) derivatives, boron‐nitrogen coordination bond (B←N)‐incorporated (hetero)arenes, cyano‐functionalized (hetero)arenes, and fused‐ring electron acceptors (FREAs). In addition, single‐component‐based all‐PSCs are also briefly discussed. The structure‐property correlations of polymer acceptors are elaborated in detail. Finally, we offer our insights into the development of new electron‐deficient building blocks with further optimized properties and the polymers built from them for efficient all‐PSCs.