Dimeric Acceptor with Small Singlet‐Triplet Energy Gap Enables Suppressed Triplet Loss and 20.85% Efficiency of Organic Solar Cells

also facilitates reverse intersystem crossing process, enabling recycling of triplet excitons. Consequently, the resulting ternary device achieves a low non-radiative energy loss of 0.194 eV and an outstanding power conversion efficiency of 20.85%. This work demonstrates an effective strategy for suppressing triplet-mediated energy losses and provides a promising avenue for advancing the performance of OSCs.