Phenothiazine derivatives as organic sensitizers for highly efficient dye-sensitized solar cells
作者:Chih-Jen Yang、Yuan Jay Chang、Motonori Watanabe、Yung-Son Hon、Tahsin J. Chow
DOI:10.1039/c2jm13961h
日期:——
A series of organic dyes containing a phenothiazine central unit were synthesized and were used effectively in the fabrication of dye-sensitized solar cells (DSSCs). A cyanoacrylate moiety was added at the C(3) position of the phenothiazine as an electron acceptor, and a triarylamine moiety was attached at the C(7) position as an electron donor. The DSSCs made with these dyes displayed remarkable quantum efficiency, ranging from 4.2–6.2% under an AM 1.5 solar condition (100 mW cm−2). A variety of substituents, i.e., methyl, hexyl and triphenylamino groups, were added at the N(10) of phenothiazine in order to optimize the incident photon-to-current conversion efficiency. Along the main chromophore a thiophenylene group was inserted at different positions to examine its influence on the properties of devices. The best performance was found in compound NSPt-C6, in which a hexyl group was attached at the N(10) of phenothiazine and a thiophenylene at the C(7) position. It displayed a short-circuit current (Jsc) of 14.42 mA cm−2, an open-circuit voltage (Voc) of 0.69 V, and a fill factor (ff) of 0.63, corresponding to an overall conversion efficiency of 6.22%. Their photophysical properties were analyzed with the aid of a time-dependent density functional theory (TDDFT) model with the B3LYP functional. Their photovoltaic behavior was further elucidated by the electrochemical impedance spectroscopy.
合成了一系列含有苯噻嗪中心单元的有机染料,并有效地用于染料敏化太阳能电池(DSSCs)的制造。在苯噻嗪的C(3)位点添加了一种氰基丙烯酸酯部分作为电子受体,同时在C(7)位点连接了三芳胺部分作为电子给体。使用这些染料制作的DSSC在AM 1.5太阳条件下(100 mW cm−2)显示出显著的量子效率,范围为4.2%至6.2%。在苯噻嗪的N(10)位点添加了多种取代基,如甲基、己基和三苯胺基,以优化入射光子到电流的转换效率。在主要染料上还在不同位置插入了噻吩苯基,以研究其对器件性能的影响。最佳表现发现于化合物NSPt-C6,其中在苯噻嗪的N(10)位点连接了己基,并在C(7)位点连接了噻吩苯基。它显示出短路电流(Jsc)为14.42 mA cm−2,开路电压(Voc)为0.69 V,填充因子(ff)为0.63,相应的整体转换效率为6.22%。借助时间相关密度泛函理论(TDDFT)模型与B3LYP泛函分析了它们的光物理性质。通过电化学阻抗谱进一步阐明了它们的光伏行为。