三苯基均三嗪基团调控敏化染料光电性能的理论研究

Theoretical Studies of Triphenyl-s-triazine Groups Regulating Photoelectric Properties of Sensitizing Dyes

为了探究更高效率的敏化染料,将三苯基均三嗪基团引入供体-受体-共轭π桥-受体(D-A-π-A)型WS-4(HB)敏化剂中,设计了7种新型染料分子,采用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)方法优化了新型敏化剂的几何构型,分析了分子的基态结构、前线轨道能级、吸收光谱、激发能及分子内电荷转移等相关性质.结果表明,三苯基均三嗪可以有效改善以三苯胺为电子给体的染料性能,其中在三苯基均三嗪上双侧连接三苯胺给体的染料HBL2表现出更低的能隙和光捕捉效率.利用Multiwfn对染料HBL2电子转移情况进行分析,结果表明,三苯基均三嗪不仅可起到电子推拉作用,还在一定程度上起到供体的作用,对分子内电荷转移起到促进作用.

By adding the 2,4,6-triphenyl-s-triazine group into the donor-acceptor-π-acceptor(D-A-π-A)configuration sensitizer,seven kinds of new sensitizers were designed.Then the methods of density functional theory(DFT)and time-dependent density functional theory(TD-DFT)were used to study the geometric con-figuration,front-line orbital energy levels,absorption spectral,excitation energy,intramolecular charge transport and other related properties.The results indicate that the 2,4,6-triphenyl-s-triazine group can effectively improve the performance of dyes,which using triphenylamine as electron donors.The dye HBL2,which attaching triphenylamine to both sides of 2,4,6-triphenyl-s-triazine,has lower band gap and higher light harvesting efficiency(LHE).The electron transfer results of the dye HBL2 analysed by the Multiwfn show that 2,4,6-triphenyl-s-triazine not only acts as electronic push-pull effect,but also acts as a donor under certain conditions.So it can promote the intramolecular charge transfer.