Four acceptor1-acceptor2-donor-acceptor2-acceptor1 (A1-A2-D-A2-A1) structural electron acceptors with different end-chains were designed and synthesized which all possessed indacenodithiophene (IDT) core, benzothiadiazole (BT) bridge as acceptor2, and rhodanine (R) end groups as acceptor1. The non-fullerene acceptor attached with ethyl group is called IDT-BT-R2 and used as control compound. And the other three of them are attached with methoxymethyl, trifluoroethyl and 1-piperidino groups generating IDT-BT-RO, IDT-BT-RF3 and IDT-BT-RN, respectively. The influence of end-chains on their optoelectronic properties were compared between four non-fullerene acceptors. Compared with IDT-BT-R2, the molecule IDT-BT-RF3 show red-shifted light absorption and lower LUMO level because of the electron withdrawing property of fluorine atoms. OSCs based on IDT-BT-RF3 display more efficient charge separation and lower degree of monomolecular recombination, allowing OSCs to show higher short-circuit current (J_sc) than the system of IDT-BT-R2. OSCs based on IDT-BT-RO also show more efficient charge separation and less monomolecular recombination. Due to the elevated LUMO level of the acceptor IDT-BT-RN, organic solar cells (OSCs) utilizing this material as acceptor display high open-circuit voltage (V_oc) of 1.10 eV and low energy loss of 0.49 eV when maintaining a relatively high power conversion efficiency (PCE) of 7.09%. We demonstrated that the end-chain engineering could finely tune the light absorption properties and energy levels of novel non-fullerene acceptors and eventually improved OSCs performance can be harvested.

设计并合成了四个具有不同末端链的受体1-受体2-供体-受体2-受体1（A1-A2-D-A2-A1）结构电子受体，它们均具有茚并二噻吩（IDT）核，苯并噻二唑（BT）桥作为受体2，和若丹宁（R）端基作为受体1。与乙基连接的非富勒烯受体称为IDT-BT-R2，用作对照化合物。它们中的其他三个分别与甲氧基甲基，三氟乙基和1-哌啶子基相连，分别生成IDT-BT-RO，IDT-BT-RF3和IDT-BT-RN。在四个非富勒烯受体之间比较了端链对其光电性能的影响。与IDT-BT-R2相比，分子IDT-BT-RF3由于氟原子的吸电子特性，显示出红移的光吸收和较低的LUMO能级。J _sc），而不是IDT-BT-R2的系统。基于IDT-BT-RO的OSC还显示出更有效的电荷分离和更少的单分子重组。由于受体IDT-BT-RN的LUMO含量升高，使用这种材料作为受体的有机太阳能电池（OSC）在维持相对较高的开路电压（V _oc）时为1.10 eV，能量损耗较低，为0.49 eV。 7.09％的高功率转换效率（PCE）。我们证明了端链工程可以精细地调节新型非富勒烯受体的光吸收性能和能级，最终可以收获改进的OSC性能。