Traditional organic photovoltaic materials exhibit low dielectric constants (ε_r) of 3 to 4, restricting the further enhancement of power conversion efficiencies (PCEs) of organic solar cells (OSCs). Herein we design and synthesize a fused-ring electron acceptor named Y6-4O through introducing an asymmetric highly polarizable oligo(ethylene glycol) side chain onto the pyrrole unit of Y6. Compared with alkylated Y6 (ε_r = 3.36), asymmetric glycolated Y6-4O shows a notably higher ε_r value of 5.13 and better solubility in nonhalogen solvents. Because of the higher ε_r value, the devices based on as-cast PM6:Y6-4O processed using toluene exhibit a higher charge separation yield, slower bimolecular recombination kinetics, and less voltage loss relative to the control devices based on PM6:Y6. Consequently, a high PCE of 15.2% is achieved for PM6:Y6-4O-based devices, whereas the PM6:Y6-based devices show PCEs of only 7.38%. 15.2% is the highest PCE for the as-cast nonhalogenated processed OSC devices, and it is also much higher than the values (<8.5%) reported for OSCs based on high-permittivity (ε_r > 5) organic photovoltaic semiconductors.

中文翻译：

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用于增强高性能光伏电子受体的介电常数和生态相容性的不对称糖基化取代

传统的有机光伏材料表现出3 到 4 的低介电常数 (ε _r )，限制了有机太阳能电池 (OSC) 功率转换效率 (PCE) 的进一步提高。在此，我们通过在 Y6 的吡咯单元上引入不对称的高度极化低聚（乙二醇）侧链，设计并合成了一种名为 Y6-4O 的稠环电子受体。与烷基化 Y6 (ε _r = 3.36) 相比，不对称乙醇化 Y6-4O 显示出显着更高的 ε _r值，为 5.13，并且在非卤素溶剂中具有更好的溶解性。由于较高的 ε _r值，与基于 PM6:Y6 的控制装置相比，使用甲苯处理的基于铸态 PM6:Y6-4O 的装置表现出更高的电荷分离率、更慢的双分子重组动力学和更小的电压损失。因此，基于 PM6:Y6-4O 的设备实现了 15.2% 的高 PCE，而基于 PM6:Y6 的设备的 PCE 仅为 7.38%。15.2% 是铸态非卤化处理 OSC 器件的最高 PCE，也远高于基于高介电常数 (ε _r > 5) 有机光伏半导体的OSC 报告的值 (<8.5%) 。