Due to the strong electron-withdrawing capability, the rhodanine unit is widely used as the acceptor of the D-π-A organic sensitizer. However, in this unit, the carboxyl group is shut out from the whole conjugation system, which affects the injection of the excited electrons, leading to poor photovoltaic performance. Herein, with the introduction of cyanoacetic acid into the rhodanine segment, two novel indoline sensitizers, CS-22 and CS-24, based on D-π-A construction are designed and synthesized. With this modification, the carboxyl group is conjugated with the whole molecule, leading to sharp enhance of light-harvesting capability of the dye and more important, quite smooth electron injection process. Moreover, the introduced long alkyl chain can also prevent the π-aggregation on TiO₂ surface and restrain the charge recombination effectively. Accordingly, using the modified acceptor, the photovoltaic performance is significantly improved: an extremly high PCE of 8.48% is obtained by CS-22 sensitized DSSC, which is the highest value among rhodanine dyes without any co-adsorbent. Our work demonstrates that the introduction of conjugated carboxyl group is greatly benefit for the improvement of rhodanine dyes in photovoltaic performance, providing a powerful strategy for the development of rhodanine based highly efficient D-π-A organic sensitizer in the future.

由于强的吸电子能力，若丹宁单元被广泛用作D-π-A有机敏化剂的受体。但是，在该单元中，羧基被整个共轭体系拒之门外，这影响了激发电子的注入，从而导致了较差的光伏性能。在本文中，随着将氰基乙酸引入罗丹宁片段中，两种新型的吲哚啉敏化剂CS-22和CS-24，基于D-π-A结构进行了设计和合成。通过这种修饰，羧基与整个分子共轭，导致染料的光收集能力急剧增强，并且电子注入过程更为重要且非常平稳。此外，引入的长烷基链还可以防止TiO ₂表面上的π-聚集并有效地抑制电荷复合。因此，使用修饰的受体，光伏性能得到显着改善：CS-22获得了8.48％的极高PCE敏化DSSC，在没有任何助吸附剂的罗丹宁染料中是最高值。我们的工作表明，引入共轭羧基对改善罗丹宁染料的光伏性能有很大帮助，为将来开发基于罗丹宁的高效D-π-A有机敏化剂提供了有力的策略。