Recent Progress of All Polymer Solar Cells with Efficiency Over 15%

All polymer solar cells (APSCs) composed of polymeric donors and acceptors have attracted tremendous attention due to their unique merits of mechanical flexibility and good film formation property, which exhibit promising applications on wearable and flexible stretchable devices. Over 18% power conversion efficiency of APSCs has been achieved benefiting from the continuous development of functional layer materials innovation and device engineering evolution. In this review, the functional layer materials that enabled the recent progress of efficient APSCs are outlined, including typical polymer donors, emerging polymer acceptors based on polymerizing small molecule acceptors strategy, interfacial materials as well as the rational design rules for corresponding functional materials. From the perspective of device engineering evolution, the film deposition and treatment techniques are introduced, which play a vital role in manipulating film morphology through properly tuning the vertical component distribution and aggregation behavior of polymers. Meanwhile, the ternary strategy is also discussed as an effective method in promoting mechanical durability, stability, and thickness‐insensitive characteristics of APSCs facing for future applications. The challenges and outlooks on this filed are finally proposed for developing high‐performance APSCs.