A series of charge-separated (CS) sensitizers with various donor modules and pyrimidine as acceptor were synthesized and employed to explore the effect of donor structure engineering on the properties of CS sensitizers and photovoltaic performances of dye-sensitized solar cells (DSSCs). Using previously reported CS sensitizer MTPA-Pyc or YD-Pyc as the model molecule, cyano group or benzotriazole were incorporated into the donor module and the electrochemical, spectral and photophysical properties were investigated. Incorporating electron-withdrawing structures enhances the intramolecular charge transfer (ICT) and conjugation of the donor module which leads to not only remarkably red-shifted absorption spectra, but also elongated lifetime of CS state of the sensitizers, thus resulting in an over 30% increase of power conversion efficiency (PCE) of the DSSCs. Combination of an electron-withdrawing benzotriazole with a strong electron-donating indoline moiety in the donor module produces the best PCE of 7.41% for DSSC based on YDBT-Pyc. Our results provide not only the rational design principles for CS sensitizers, but also insight into the feasibility of CS sensitizers for high performance photovoltaic applications.

合成了一系列带有各种供体模块和嘧啶作为受体的电荷分离（CS）敏化剂，并用于探索供体结构工程对CS敏化剂性能和染料敏化太阳能电池（DSSC）的光伏性能的影响。使用先前报道的CS敏化剂MTPA-Pyc或YD-Pyc作为模型分子，将氰基或苯并三唑掺入给体模块中，并研究了其电化学，光谱和光物理性质。结合吸电子结构增强了分子内电荷转移（ICT）和施主模块的结合，这不仅导致吸收光谱显着红移，而且延长了敏化剂CS态的寿命，因此导致超过30％的增加DSSC的功率转换效率（PCE）。供体模块中吸电子的苯并三唑与强供电子二氢吲哚部分的结合产生基于YDBT-Pyc的DSSC最佳PCE为7.41％。我们的研究结果不仅为CS增感剂提供了合理的设计原理，而且为CS增感剂在高性能光伏应用中的可行性提供了见识。