The power conversion efficiency (PCE) of organic solar cells (OSCs) devices has surpassed 19% owing to the blooming of fused-ring nonfullerene acceptors (NFAs), especially for acceptor–donor–acceptor (A–D–A) type NFAs. However, the structural effect of the angular/linear fusion mode and number of fused rings for A–D–A type NFAs on the photovoltaic performance in OSCs devices remains unclear. Herein, the A–D–A type NFAs (F-0Cl, IDIC8-H, and ITIC) have been selected to obtain the intrinsic role of structural design strategies including the angular/linear fusion mode and the number of fused rings. The results indicate that compared to the linear fusion mode in ITIC, the angular fusion mode in F-0Cl effectively diminishes electronic vibrational coupling within the low-frequency range, leading to lower charge reorganization during the exciton diffusion process. Meanwhile, it facilitates the generation of multiple charge transfer mechanisms at the donor/acceptor (D/A) interface and increases the rates of hole transfer. On the other hand, the decreased number of fused rings of NFAs could inhibit the exciton decay and charge recombination but increase the rates of exciton diffusion and exciton dissociation for individual NFAs and the rates of electron separation for D/A interface. This work provides theoretical insights into structural design strategies, such as linear/angular fusion, and the number of fused rings of NFA, which presents a promising outlook for further enhancing PCE of high-performance A–D–A type NFAs.

中文翻译：

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熔融模式和熔融环数量：它们对有机太阳能电池中受体-供体-受体非富勒烯受体的影响


由于熔融环非富勒烯受体 （NFA） 的蓬勃发展，有机太阳能电池 （OSC） 器件的功率转换效率 （PCE） 已超过 19%，尤其是受体-供体-受体 （A-D-A） 型 NFA。然而，A-D-A 型 NFA 的角/线性融合模式和熔融环数量的结构影响对 OSCs 器件中光伏性能的影响仍不清楚。在此，选择了 A-D-A 型 NFA（F-0Cl、IDIC8-H 和 ITIC）以获得结构设计策略的内在作用，包括角度/线性融合模式和熔融环的数量。结果表明，与 ITIC 中的线性融合模式相比，F-0Cl 中的角融合模式有效地减少了低频范围内的电子振动耦合，导致激子扩散过程中的电荷重组较低。同时，它有助于在供体/受体 （D/A） 界面处产生多个电荷转移机制，并提高空穴转移速率。另一方面，NFA 熔合环数量的减少可以抑制激子衰变和电荷复合，但会增加单个 NFA 的激子扩散和激子解离速率以及 D/A 界面的电子分离速率。这项工作为结构设计策略提供了理论见解，例如线性/角度融合以及 NFA 的熔融环数量，为进一步增强高性能 A-D-A 型 NFA 的 PCE 提供了广阔的前景。