A new main-chain twisted small molecular acceptor with nonhalogenated end groups (i-IEICO) is designed and synthesized. In contrast to its planar analogue IECIO, i-IEICO possesses an obviously twisted backbone, leading to significant hypsochromic shift in film absorption, slight enhancement in solution extinction coefficient, and significantly elevated molecular energy level. Benefited from these features, i-IEICO is matched well with two wide band gap polymer donor materials (J52 and PBDB-T) both in absorption spectra and molecular energy levels. Relative to the planar-molecule IEICO-based devices, the open-circuit voltage (V_OC), short-circuit current density, and fill factor of the i-IEICO-based devices are simultaneously improved, giving rising to a 10.48% (with J52) and 8.79% (with PBDB-T) power conversion efficiency, respectively. Moreover, J52:i-IEICO device exhibits a high V_OC of 0.96 V accompanied by a small energy loss of 0.64 eV, which can be further improved to 1.01 V and 0.59 eV for the PBDB-T-based device. The obtained V_OC of i-IEICO-based devices are among one of the highest values of either J52 or PBDB-T-based binary devices, suggesting the effectiveness of main-chain twisted strategy coupled with end-group modification to achieve highly efficient nonfullerene acceptors with low energy loss and high V_OC.

中文翻译：

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通过主链扭曲的小分子受体实现的具有高开路电压和低能量损耗的高效聚合物太阳能电池

设计并合成了一种新的带有非卤端基的主链扭曲小分子受体（i-IEICO）。与平面模拟IECIO相比，i-IEICO具有明显扭曲的骨架，从而导致薄膜吸收发生显着的变色，溶液的消光系数略有提高，并且分子能级显着提高。得益于这些功能，i-IEICO在吸收光谱和分子能级方面与两种宽带隙聚合物供体材料（J52和PBDB-T）非常匹配。相对于基于平面分子IEICO的器件，开路电压（V _OC），同时改善了基于i-IEICO的设备的短路电流密度和填充系数，分别提高了10.48％（使用J52）和8.79％（使用PBDB-T）的功率转换效率。此外，J52：I-IEICO装置表现出高的V _OC伴有0.64 2eV的能量损失小，这可以进一步提高到1.01 V和0.59 eV的对于基于PBDB-T-设备0.96的V。获得的i-IEICO的V _OC的设备是基于J52或PBDB-T的二进制设备的最高价值之一，这表明主链扭曲策略与端基修饰相结合以实现具有低能量损耗和高V的高效非富勒烯受体的有效性_超频。