染料敏化剂是染料敏化太阳能电池中关键的光电转换材料, 其受光激发后, 电子由低能级基态跃迁到高能级激发态从而产生有效的电势差。设计和筛选优异性能的染料敏化剂有利于提升其光电转化效率。本文以相关实验研究为背景, 设计了一系列具有不同桥位基团的四硫富瓦烯(TTF)类纯有机染料敏化剂, 利用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)对其光电转化及分子内电子转移特性进行了系统研究, 通过比较筛选出了高性能的四硫富瓦烯类染料敏化剂。研究结果表明, 以环戊联噻吩及其衍生物作为桥位基团的四硫富瓦类染料敏化剂的整体性能更佳, 主要表现在较好的电荷分离态、拓宽的光谱吸收范围、提升的光捕获效率以及增强的分子内电子转移(IET)性能等。

Dye sensitizers are the key photoelectric conversion materials in dye-sensitized solar cells (DSSCs). The electrons in sensitizers transfer from the low level of ground state to the high level of excited state and generate effective potential difference when sensitizers are excited by light. Designing and screening sensitizer with excellent properties is beneficial to promote their photoelectric conversion efficiency. A series of tetrathiafulvalene (TTF)-based metal-free dye sensitizers with different π-bridge were designed based on the relevant experimental study, and their photoelectric conversion and the intramolecular electron transfer characteristics were systematically investigated by using density functional theory (DFT) and time-dependent DFT. Results show that the overall performance of TTF-based metal-free dye sensitizer with cyclopentathiophene and its derivatives as π-bridge was significantly improved in terms of the better charge separation state, broadened spectral absorption coverage rage, improved light-harvesting efficiency and enhanced intramolecular electron transfer performance.