Abstract

The emergence of the latest generation of small-molecule acceptor (SMA) materials, with Y6 as a typical example, accounts for the surge in device performance for organic solar cells (OSCs). This study proposes two new acceptors named Y6-C2 and Y6-C3, from judicious alteration of alkyl-chains branching positions away from the Y6 backbone. Compared to the Y6, the Y6-C2 exhibits similar optical and electrochemical properties, but better molecular packing and enhanced crystallinity. In contrast, the Y6-C3 shows a significant blue-shift absorption in the solid state relative to the Y6 and Y6-C2. The as-cast PM6:Y6-C2-based OSC yields a higher power conversion efficiency (PCE) of 15.89% than those based on the Y6 (15.24%) and Y6-C3 (13.76%), representing the highest known value for as-cast nonfullerene OSCs. Prominently, the Y6-C2 displays a good compatibility with the PC₇₁BM. Therefore, a ternary OSC device based on PM6:Y6-C2:PC₇₁BM (1.0:1.0:0.2) was produced, and it exhibits an outstanding PCE of 17.06% and an impressive fill factor (FF) of 0.772. Our results improve understanding of the structure-property relationship for state-of-the-art SMAs and demonstrate that modulating the structure of SMAs via fine-tuning of alkyl-chains branching positions is an effective method to enhance their performance.

中文翻译：

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改变烷基链的支链位置以提高小分子受体对高效非富勒烯有机太阳能电池的性能

摘要

以Y6为例，最新一代的小分子受体（SMA）材料的出现说明了有机太阳能电池（OSC）器件性能的飞速增长。这项研究提出了两个新的受体，分别命名为Y6-C2和Y6-C3，这是通过明智地改变远离Y6主链的烷基链分支位置来实现的。与Y6相比，Y6-C2具有相似的光学和电化学性质，但分子堆积更好，结晶度更高。相反，相对于Y6和Y6-C2，Y6-C3在固态下显示出显着的蓝移吸收。铸造后的基于PM6：Y6-C2的OSC的功率转换效率（PCE）比基于Y6（15.24％）和Y6-C3（13.76％）的功率转换效率更高，代表了已知的最高值。铸造非富勒烯OSC。突出地，₇₁ BM。因此，生产了基于PM6：Y6-C2：PC ₇₁ BM（1.0：1.0：0.2）的三元OSC器件，它具有出色的PCE为17.06％和令人印象深刻的填充因子（FF）为0.772。我们的结果提高了对最新型SMA的结构-性质关系的理解，并证明通过微调烷基链分支位置来调节SMA的结构是增强其性能的有效方法。