Four novel organic dyes including three based on dibenzosilole (YS01â03) and one based on fluorene (YS04) were synthesized, and their photophysical properties and dye-sensitized solar cell (DSC) performances were characterized. The silicon-containing dibenzosilole-based dyes (YS01â03) were superior to the carbon analogue fluorene-based dye YS04 in incident-photon-to-current conversion efficiency (IPCE), and total solar-to-electric conversion efficiency (η), with YS03, which has the bulkiest and most branched electron donor group, achieving the highest η of 5.07% compared to 2.88% of YS04. To better understand how silicon influences the excited state oxidation potentials (S+/*) and absorption maxima (λmax), the equilibrium molecular geometries of dyes YS01â04 were calculated using density functional theory (DFT) utilizing B3LYP energy functional and DGDZVP basis set. It was shown that the torsion angles (θ1 and θ2) across the biphenyl linkages of dyes containing silicon (YS01â03) were less twisted than that of the silicon-free dye (YS04), which enhanced the ÏâÏ* overlap, and that translated into photocurrent enhancements in the silicon-containing dyes YS01â03. Moreover, the vertical electronic excitations and S+/* of dyes YS01â04 were studied using different long-range corrected time-dependent DFT methods, including CAM-B3LYP, LC-BLYP, WB97XD, and LC-wPBE at the basis set level DGDZVP. Excellent agreement between the calculated, using CAM-B3LYP/DGDZVP, and experimental results was found.
合成了四种新型有机
染料,包括三种基于二苯并
硅啶(YS01–03)和一种基于
萘的
染料(YS04),并对其光物理特性和
染料敏化太阳能电池(
DSC)的性能进行了表征。含
硅的二苯并
硅啶基
染料(YS01–03)在入射光子转电流效率(IPCE)和总太阳能转电能效率(η)方面优于碳基类似物的
萘基
染料(YS04),其中YS03具有最大体积和最为分支的电子给体基团,实现了最高的η值为5.07%,而YS04的η值仅为2.88%。为了更好地理解
硅如何影响激发态氧化电位(S+/*)和吸收最大值(λmax),利用密度泛函理论(DFT)计算了
染料YS01–04的平衡分子几何结构,采用B3LYP能量泛函和DGDZVP基组。结果表明,含
硅染料(YS01–03)中通过
联苯链接的扭转角(θ1和θ2)比不含
硅的
染料(YS04)扭转程度更小,从而增强了π–π*重叠,这转化为含
硅染料YS01–03中的光电流增强。此外,通过不同的长程校正时间相关DFT方法,包括CAM-B3LYP、LC-BLYP、W
B97XD和LC-wPBE,研究了
染料YS01–04的垂直电子激发和S+/*。使用CAM-B3LYP/DGDZVP计算的结果与实验结果之间具有很好的吻合。