Organic Solar Cells with Over 19% Efficiency Enabled by a 2D‐Conjugated Non‐Fullerene Acceptor Featuring Favorable Electronic and Aggregation Structures

of 0.928 V. These results indicate the importance of the 2D π-expansion strategy for the delicate regulation of the electronic structures and crystalline behaviors of the non-fullerene acceptors to achieve superior photovoltaic performance, aimed at significantly promoting further development of OSCs.