新型四硫富瓦烯-三苯胺类光敏染料理论研究

在简单结构的D-π-A三苯胺光敏染料(YD1)中引入不同数量的四硫富瓦烯(TTF)单元作为次级电子给体以增强有机光敏染料的给电子能力，设计了两个结构分别为D-D-π-A (YD2)以及2D-D-π-A (YD3)的光敏染料分子，并且采用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)分别模拟计算了纯光敏剂分子及其吸附二氧化钛团簇后的几何构型、电子结构以及光物理性能。采用周期性密度泛函理论模拟计算光敏染料分子在二氧化钛(101)面吸附的表面形貌以及态密度(DOS)。计算结果表明，TTF单元的引入不仅可以有效减少光敏染料分子的团聚，还可以提升其吸收性能。此外，光吸收效率(LHE)、电子注入驱动力(ΔG^inject)以及DOS的计算结果显示，YD2和YD3理论上可以呈现出比YD1更高的短路电流密度(J_sc)以及开路电压(V_oc)。因此，通过本文的理论研究表明，TTF单元可以作为有机光敏染料中的次级电子给体来改善光敏染料的性能。

Theoretical Investigation of Novel Tetrathiafulvalene- Triphenylamine Sensitizers

Two novel sensitizers with D-D-π-A (YD2) and 2D-D-π-A (YD3) structures were designed by introducing different numbers of tetrathiafulvalene (TTF) unit as the auxiliary electron donor based on the simple D-π-A triphenylamine sensitizer (YD1) to enhance the electron donating ability. The geometries, electronic structures, and optical properties of YD1－3 before and after binding to TiO₂ clusters were investigated. Owing to introduction of TTF unit, YD2 and YD3 show larger steric hindrance and a narrower band gap than YD1. Moreover, the estimated light-harvesting efficiency (LHE), injection driving force (ΔG^inject) values, and density of states (DOS) calculations indicate that YD2 and YD3 should show higher short-circuit photocurrent density (J_sc) and open-circuit photovoltage (V_oc) than YD1 with the presence of TTF unit. All of the results indicate that TTF unit can be used as an auxiliary electron donor in organic sensitizers to improve their photovoltaic properties.