19.5% Efficiency in binary organic solar cells with enhanced stability using a flexible chain-tethered dimeric acceptor with unprecedentedly high yield

In this paper, an alkyl-chain-linked strategy is employed to synthesize a dimeric acceptor, DPhC8Y, which achieves simultaneous enhancements in device efficiency and stability while also exhibiting an unprecedentedly high production yield compared to other “giant molecular acceptors” for organic solar cells (OSCs). Compared to the monomer DTY6, DPhC8Y contains improved crystalline ordering and refined phase separation, thereby reducing non-radiative loss, suppressing bulk and interface recombination, and decreasing trap density. On the other hand, the dimer acceptor possesses an intrinsically higher glass transition point. Through performance evaluation, the binary device of D18:DPhC8Y blend demonstrates 19.50% efficiency with remarkably over 80% fill factor (FF), surpassing those of D18:DTY6 (18.25% and 76.42%). Meanwhile, the dimer-based active layer displays significantly enhanced storage and thermal stability in the device. Our report showcases the possibility of achieving OSCs with concurrent decent efficiency, stability, and cost-effectiveness through smart material and synthesis design.