Significant nonradiative energy loss and short exciton diffusion length in organic solar cells (OSCs) are two major obstacles to achieving state-of-the-art efficiencies. It is crucial to conduct a study on the intensive mechanism and improvement strategies for future breakthroughs in the efficiency of OSCs. In this work, nonradiative energy loss and exciton diffusion length are optimized simultaneously by incorporating a guest acceptor (LA15) to construct ternary OSC (D18:L8-BO:LA15). Firstly, LA15 exhibits excellent compatibility with the host acceptor L8-BO, and effectively improves the fluorescence quantum efficiency (FLQY), resulting in suppressed non-radiative energy loss. Moreover, LA15 effectively prolongs the fluorescent lifetime of the acceptor phase from 0.85 to 1.12 ns, leading to larger exciton diffusion length, which is beneficial for reducing geminate recombination. Besides, the addition of LA15 optimizes the crystallinity of the active layer with amplified charge transport capacity. As a result, the optimized D18:L8-BO:LA15 device achieves ultralow nonradiative energy loss of 0.18 eV and improved fill factor (FF) with high efficiency up to 19.13%. These results highlight the crucial roles of regulating FLQY and exciton lifetime in achieving high-efficiency OSCs.

有机太阳能电池（OSC）中显着的非辐射能量损失和较短的激子扩散长度是实现最先进效率的两个主要障碍。开展OSC集约机制和改进策略的研究对于未来OSC效率的突破至关重要。在这项工作中，通过结合客体受体（LA15）构建三元OSC（D18：L8-BO：LA15），同时优化非辐射能量损失和激子扩散长度。首先，LA15与主体受体L8-BO表现出优异的相容性，有效提高荧光量子效率（FLQY），从而抑制非辐射能量损失。此外，LA15有效地将受体相的荧光寿命从0.85 ns延长至1.12 ns，从而导致更大的激子扩散长度，这有利于减少双子复合。此外，LA15的添加优化了活性层的结晶度，并增强了电荷传输能力。因此，优化后的 D18:L8-BO:LA15 器件实现了 0.18 eV 的超低非辐射能量损失，并提高了填充因子 (FF)，效率高达 19.13%。这些结果凸显了调节 FLQY 和激子寿命在实现高效 OSC 中的关键作用。