中文摘要：

通过密度泛函理论（Density Functional Theory,DFT）和依时密度泛函理论（Time-Dependent Density Functional Theory,TD-DFT）,研究了染料分子结构中烷基链对染料敏化太阳能电池短路电流（Jsc）和开路电压（Voc）的影响.通过计算孤立染料的激发态电子注入TiO2导带的驱动力（ΔGinject）和光捕获效率（LHE）,分析了烷基链对Jsc的影响.引入一个简单的TiO2吸附模型来模拟染料与TiO2之间的相互作用,并计算了影响Voc的垂直偶极矩和激发态时TiO2上的电荷转移量.结果表明,Jsc和Voc随烷基链的增长而增大（从1增大到13）,而Voc在链长为13时开始减小.计算结果和实验结果相吻合,表明该计算模型可有效运用于钌系染料的理论分析,并可为设计高性能染料提供参考.

英文摘要：

In order to investigate the effect of alkyl chain of ruthenium-based dyes on dye-sensitized solar cells（DSSCs）,density functional theory（DFT）and time-dependent DFT methods were used to characterized the two important parameters of the solar cells,short-circuit current density（Jsc）and open-circuit voltage（Voc）.Light-harvesting efficiency（LHE）and driving force of electron injection（ΔGinject）were calculated to provide an insight into the effect of alkyl chain on Jsc.A simple and effective dye-titanium dioxide model which was adopted to simulate the interfacial interaction between dye and semiconductor,was applied to ruthenium dyes for the first time.The vertical dipole moments impacting Vocand the number of electrons transferred from the dye to TiO2 were investigated.Our conclusions stress that large vertical dipole moments are crucial to obtain high Voc.And,the calculated results are in considerable agreement with the published experimental data and clarify the effect of the alkyl chain of the dye molecule on Jscand Vocof the solar cell.This calculation model is reliable and reasonable for the theoretical analysis of the ruthenium dyes.This may provide a guidance in the designing of high-performance sensitizers.