New Phase for Organic Solar Cell Research: Emergence of Y-Series Electron Acceptors and Their Perspectives

With the recent emergence of a new class of high-performance nonfullerene acceptors (NFAs), organic solar cells (OSCs) have entered a new phase of research featuring high power conversion efficiencies (PCEs). In this Perspective, we summarize the recent progress made from Y-series NFAs and the matched polymer donors and analyze the molecular design strategies for boosting device performance. We also perform a PCE prediction of OSCs and propose requirements for NFAs, aiming at a PCE of 20%, which is comparable to those of Si and perovskite-based counterparts. Finally, we assess three factors of efficiency, stability, and cost and outline the challenges facing OSCs and the future development directions of OSCs. This work is expected to provide valuable suggestions with a comprehensive view to advance practical application of OSCs.