Extending exciton lifetime and optimizing active-layer morphology simultaneously to advance power conversion efficiency (PCE) of organic solar cells (OSCs) still encounter great challenges by conventional additive strategies. Herein, to address these issues, a multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitter of BNS-H1 containing heteroatom-embedded polycyclic aromatic hydrocarbon is innovatively served as a dual-functional solid additive (DFSA) in OSCs. The primary studies on the PM6:Y6 system indicate that BNS-H1 plays an exceptional dual-functional role in promoting π-π stacking of Y6 component and optimizing active-layer morphology. Meanwhile, the steady/transient photoluminescence spectra and transient photocurrent measurements further reveal that incorporating BNS-H1 with the system enhances emission of PM6 component, extend exciton lifetime and diffusion distance. Consequently, four types of binary OSCs demonstrate a notable improvement in PCE processed by 1.0 wt% BNS-H1. Specifically, the BNS-H1-treated OSCs with PM6:Y6 and PM6:BTP-eC9 systems achieve outstandingly increasing PCEs of 17.4% and 18.8% compared to their BNS-H1-free control devices, respectively. Furthermore, device stability of the BNS-H1-treated PM6:Y6 devices is significantly enhanced. Notably, the approaching 19% efficiency is one of the highest PCEs in the reported non-volatile additives treated binary OSCs. Our work highlights the significant potential of MR-TADF emitter as a DFSA in OSCs for boosting PCEs.

中文翻译：

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MR-TADF 发射体作为双功能固体添加剂，可延长激子寿命并优化有机太阳能电池的形态，效率约为 19%


同时延长激子寿命和优化活性层形态以提高有机太阳能电池（OSC）的功率转换效率（PCE）仍然面临传统添加剂策略的巨大挑战。在此，为了解决这些问题，含有杂原子嵌入多环芳烃的BNS-H1的多重共振热激活延迟荧光（MR-TADF）发射器被创新性地用作OSC中的双功能固体添加剂（DFSA）。对PM6:Y6体系的初步研究表明，BNS-H1在促进Y6组分的π-π堆积和优化活性层形貌方面发挥着特殊的双重功能作用。同时，稳态/瞬态光致发光光谱和瞬态光电流测量进一步表明，将BNS-H1与系统结合可以增强PM6成分的发射，延长激子寿命和扩散距离。因此，四种类型的二元 OSC 在经 1.0 wt% BNS-H1 处理后的 PCE 方面表现出显着的改善。具体而言，与不含 BNS-H1 的控制装置相比，使用 PM6:Y6 和 PM6:BTP-eC9 系统的 BNS-H1 处理 OSC 的 PCE 分别显着提高了 17.4% 和 18.8%。此外，经 BNS-H1 处理的 PM6:Y6 器件的稳定性显着增强。值得注意的是，接近 19% 的效率是已报道的非挥发性添加剂处理的二元 OSC 中最高的 PCE 之一。我们的工作强调了 MR-TADF 发射器作为 OSC 中的 DFSA 在提高 PCE 方面的巨大潜力。