The impact of alkyl side chain substitutions of small molecule non-fullerene acceptors (NFAs) on their photovoltaic performance of bulk heterojunction (BHJ) organic solar cells (OSCs) has been studied. To further investigate the effects of side chains, in this work a series of NFAs based on a Y6 core derivatized with various alkyl groups of 6-phenylhexyl, 6-phenoxylhexyl and n-octyl (named Y6-phC6, Y6-phOC6, and Y6-nC8) are synthesized, and their detailed structure-properties correlations are investigated. The results in terms of UV–vis absorption, cyclic voltammetry and density functional theory calculation show the variations of alkyl chains have little influence on the absorption spectra and energy levels. However, these seemingly negligible changes have a pronounced impact on the molecular aggregation or crystallinity in the neat films, which in turn influences the photovoltaic properties of these devices resulting from the various microstructures of the BHJ blends and carrier dynamics in the corresponding devices. Among these three systems, OSCs based on a blend of Y6-phC6 and polymer donor PM6 show the highest power conversion efficiency of 11.77%.

研究了小分子非富勒烯受体（NFA）的烷基侧链取代对其本体异质结（BHJ）有机太阳能电池（OSC）的光伏性能的影响。为了进一步研究侧链的影响，在这项工作中，一系列基于基于Y6核心的NFA，这些核心被6-苯基己基，6-苯氧基己基和正辛基（称为Y6-phC6，Y6-phOC6和Y6）的各种烷基衍生化-nC8）进行合成，并研究其详细的结构-性质相关性。以紫外线-可见光表示的结果吸收，循环伏安法和密度泛函理论计算表明，烷基链的变化对吸收光谱和能级几乎没有影响。然而，这些看似微不足道的变化对纯净薄膜中的分子聚集或结晶度产生了显着影响，继而影响了这些器件的光伏性能，这是由BHJ共混物的各种微观结构和相应器件中的载流子动力学引起的。在这三个系统中，基于Y6-phC6和聚合物供体PM6的混合物的OSC表现出最高的功率转换效率，为11.77％。