Description Non-fullerene acceptors (NFAs) are currently a major focus of research in the development of bulk-heterojunction organic solar cells (OSCs). In contrast to the widely used fullerene acceptors (FAs), the optical properties and electronic energy levels of NFAs can be designed and readily tuned. NFA-based OSCs can also achieve greater thermal stability and photochemical stability, as well as longer device lifetimes, than their FA-based counterparts.Recent developments have led to a rapid increase in power conversion efficiencies for NFA OSCs, with values now exceeding 15% in a single junction cell, and >17% for a tandem cell, demonstrating the viability of using NFAs to replace FAs in next-generation high-performance OSCs.Y6 is a non-fullerene acceptor-donor-acceptor (A-D-A) type small molecular acceptor (SMA) with flexible alkyl chains and a centrally fused ring. It has a ladder-type electron-deficient core, which can be blended with PM6 for organic photovoltaic applications.Y6 is a non-fullerene acceptor (NFA) that uses an electron-deficient molecular core to obtain a low bandgap with improved electron affinity. OPV devices made from Y6 can reach exceptionally high performances in single-junction devices, with a maximum PCE reported of 15.7% (14.9% certified by Enli Tech Laboratory) when paired with PM6. Y6 is versatile and can be employed in both conventional and inverted OPV device architectures and can maintain a high PCE with varying active layer thicknesses (13.6% in thick 300 nm layers).