Aggregation‐Induced Emission Molecular Design for Mitigating Non‐Radiative Energy Loss in Organic Solar Cells

Abstract

ABSTRACT Non‐radiative energy loss remains a critical bottleneck limiting the open‐circuit voltage ( V OC ) and efficiency of organic solar cells (OSCs). Here, we introduce a molecular design strategy that leverages aggregation‐induced emission (AIE) to suppress aggregation‐caused quenching and enhance solid‐state photoluminescence quantum yield (PLQY), thereby mitigating non‐radiative recombination. A prototypical AIE motif, tetraphenylethylene, was incorporated into the terminal group of a Y‐series non‐fullerene acceptor to yield dTPE, which exhibits distinct AIE characteristics not previously observed in high‐performance Y‐series acceptors. Photoluminescence studies reveal that dTPE achieves a threefold enhancement in PLQY compared to L8BO‐C4 in the film, leading to an electroluminescence external quantum efficiency more than an order of magnitude higher than that of D18:L8BO‐C4. Consequently, the binary D18:dTPE device achieves a remarkably low non‐radiative recombination loss of 0.130 eV. When incorporated as a guest into D18:L8BO‐C4 blends, dTPE enables a non‐radiative voltage loss of only 0.190 eV and an unprecedented V OC of 0.93 V, yielding an efficiency of 20.5%. To our knowledge, this represents the highest V OC reported for OSCs with efficiencies above 20%. This work establishes AIE molecular design as an effective pathway to overcome intrinsic limitations of Y‐series acceptors and provides guiding principles for mitigating non‐radiative energy loss in next‐generation OSCs.