Symmetric and asymmetric non-fullerene acceptors cooperate synergistically for ternary optoelectronic devices

초록

We report two new asymmetric non-fullerene acceptors, A-YBO-2F and A-YBO-2Cl, as third components in organic solar cells (OSCs) and organic photodetectors (OPDs). These asymmetric D-A acceptors, with one terminal group removed based on a same it-conjugated backbone, exhibit blue-shifted complementary absorption and shallower energy levels compared to symmetric A-D-A acceptors (Y6). Additionally, they show good miscibility with the A-D-A type Y6, forming an alloy-like phase with Y6 that features an elevated conduction band and enhanced molecular packing through stronger dipole-dipole interactions. This leads to significant improvement in the photoelectrical characteristics of OSCs and reduced dark current in OPDs. As a result, the ternary OSC with A-YBO-2Cl achieves a power conversion efficiency of 18.37 %, surpassing the 16.95 % of the binary device. Additionally, the ternary OPD with A-YBO-2Cl shows a significantly lower dark current density of 1.06 pA cm-2 at V -> 0 V and a higher specific detectivity of 6.14 x 1012 Jones at 808 nm compared to its binary counterpart. These findings demonstrate that combining asymmetric D-A and symmetric A-D-A acceptors with a same conjugated framework effectively controls miscibility, energy levels, morphology, and performance in both OSCs and OPDs, offering a promising strategy for advancing organic semiconductor technology.

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