One of the effective ways to improve the short-circuit current density (J_sc) of polymer solar cells (PSCs) is to develop near-infrared (NIR) nonfullerene small molecule acceptors (SMAs). Herein, a novel NIR acceptor-donor-donor-acceptor (A-D-D-A)-type SMAs, C6-IDT2-DFIC which is derived from previously reported IDT2-DFIC, was designed and synthesized. By replacing the phenylhexyl group with the hexyl side-chain, the C6-IDT2-DFIC exhibits a wide absorption range in the 550–900 nm, strong intermolecular interactions, higher and more balanced charge mobilities. The device with the PBDB-T:C6-IDT2-DFIC blend film showed a power conversion efficiency (PCE) of 12.33% with a J_sc of 22.57 mA cm⁻², which is higher than that of the PBDB-T:IDT2-DFIC device (10.06% with a J_sc of 16.06 mA cm⁻²). More interestingly, the J_sc of the PBDB-T:C6-IDT2-DFIC device is one of the highest current densities from PBDB-T-based PSCs with optoelectronic response below 900 nm. Our work clearly indicate that side chain engineering is useful to achieve high J_sc of PSCs.

改善聚合物太阳能电池（PSC）短路电流密度（J _sc）的有效方法之一是开发近红外（NIR）非富勒烯小分子受体（SMA）。本文中，设计并合成了一种新型的近红外受体-供体-受体-受体（ADDA）型SMA，即C6-IDT2-DFIC，它是从先前报道的IDT2-DFIC衍生而来的。通过用己基侧链取代苯基己基，C6-IDT2-DFIC在550-900 nm范围内显示出较宽的吸收范围，强大的分子间相互作用，更高且更平衡的电荷迁移率。带有PBDB-T：C6-IDT2-DFIC混合膜的器件的功率转换效率（PCE）为12.33％，J _sc为22.57 mA cm ^-2，这比PBDB-T：IDT2-DFIC器件的要高（10.06％，J _sc为16.06 mA cm ^-2）。更有趣的是，PBDB-T：C6-IDT2-DFIC器件的J _sc是基于PBDB-T的PSC的最高电流密度之一，其光电响应低于900 nm。我们的工作清楚地表明，侧链工程对实现PSC的高J _sc很有用。