2种三聚茚基三芳胺染料的合成及其光伏性能

Synthesis and Photovoltaic Performance of Two Triarylamine Organic Dyes Based on Truxene

以三聚茚基三芳胺为给电子单元,以绕单宁-3-乙酸为受电子单元,设计合成了2种三聚茚基三芳胺染料六乙基三聚茚胺饶丹宁乙酸(MXD8)和六乙基三聚茚胺环氧噻吩饶丹宁乙酸(MXD9)。光学测试表明,该类染料光谱响应范围宽,摩尔吸光系数高。结合2种染料的紫外-可见光谱和循环伏安曲线,确定了染料的电子基态和激发态能级位置。结果表明,2种染料的能级位置符合染料敏化太阳能电池的要求。将它们用作染料敏化太阳能电池中的光敏化剂,在AM1.5-100×10-3 W/cm2的光强下,MXD8敏化电池的开路电压(VOC)为614 mV,短路电流密度(JSC)为5.76×10-3 A/cm2,填充因子(FF)为0.66,总光电转换效率为2.33%。尽管MXD9引入3,4乙撑二氧噻吩作为共轭桥,其光电转换效率却较MXD8低(1.27%)。阻抗测试表明,MXD9光电转换效率较低的原因主要是电子更容易复合。该结果表明,电子复合可能与分子共轭体系增大导致极化率增加有关。

The synthesis,characterization,and photovoltaic performance of two new organic dyes,hexapropyltruxeneamino-rhodanine-3-acetic acid（MXD8） and hexapropyltruxeneamino-3,4-ethylenedioxythiophene-rhodanine-3-acetic acid（MXD9）,were reported.The two dyes contain truxene-based triarylamine as electron donor and a rhodanine-3-acetic acid as electron acceptor.It is found that the two dyes exhibit broad absorption and high molar absorption coefficients.The ground and the excited state levels of the two dyes were determined by using the cyclic voltammetry and the optical absorption spectroscopy.The results show the HOMO and LUMO levels of two dyes are suitable for dye-sensitized solar cells.The dyes were applied into nanocrystalline TiO2 dye-sensitized solar cells through standard operations.Under simulated AM 1.5 irradiation（100×10-3 W/cm2）,MXD8 sensitized cell afforded a short-circuit photocurrent density（JSC） of 5.76×10-3 A/cm2,an open-circuit voltage（VOC） of 614 mV,and a fill factor（FF） of 0.66,corresponding to an overall conversion efficiency（η） of 2.33%.In contrast,though 3,4-ethylenedioxythiophene（EDOT） unit was introduced as the π-bridge,MXD9 sensitized cell gave a lower efficiency of 1.72%.A significantly larger extent of charge recombination between the injection electron and I2 and/or I-3 acceptor species was found for MXD9 dyes than MXD8 dyes based on the electrochemical impedance spectroscopy measurements,consequently,leading to a lower efficiency.These results suggest that the charge recombination may be correlated to the increased polarizability of the larger truxene-based triarylamine dyes.From our findings,we propose that the functionalized-truxene is a promising donor unit for the future development of organic sensitizers.