Conformational effect of symmetrical squaraine dyes on the performance of dye-sensitized solar cells
Conformational effect of symmetrical squaraine dyes on the performance of dye-sensitized solar cells
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DOI：
10.1039/c2ta00883a
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发表时间：
2013
影响因子：
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通讯作者：
Takeshi Maeda;Sho Mineta;H. Fujiwara;Hidekazu Nakao;S. Yagi;H. Nakazumi
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文献类型：
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作者：
Takeshi Maeda;Sho Mineta;H. Fujiwara;Hidekazu Nakao;S. Yagi;H. Nakazumi
合成了一种对称的方酸染料SQM 1a，通过与不对称的单羧基方酸染料SQM 1b和标准方酸染料MSQ的比较，研究了二氰基乙烯基的位阻效应对染料敏化太阳能电池性能的影响.浸渍在染料溶液中的TiO 2薄膜的FT-IR光谱表明，染料和TiO 2之间的连接是由染料的π-共轭上对称引入的两个羧基形成的。SQM 1a的对称和构象锁定结构导致非辐射衰减速率降低，这可能是由于抑制了方酸的光异构化。根据非辐射衰减的发现，用SQM 1a制备的DSSC表现出显著增强的短路电流密度，这揭示了来自SQM 1a的双锚定和构象锁定结构的有效电子注入。因此，用SQM 1a制造的DSSC的性能高于用SQM 1b和MSQ制造的DSSC的性能。这表明通过限制对称方酸菁染料的构象可以得到实质性的优点。
A symmetrical squaraine dye altered to possess dicyanovinylene functionality on a carbonyl group of the cyclobutene core (SQM1a) was synthesized to elucidate the effects of the conformationally locked-in cis-like form ensured by the steric repulsion of dicyanovinylenes on the performance of dye-sensitized solar cells (DSSCs) through a comparison with an unsymmetrical analogue bearing one carboxy group (SQM1b) and a standard squaraine dye (MSQ). The FT-IR spectrum of the TiO2 thin film immersed in the dye solution suggested that the linkages between the dye and TiO2 were formed by both carboxy groups symmetrically incorporated on the π-conjugation of dyes. The symmetrical and conformationally locked structure of SQM1a brought about a decrease in the non-radiative decay rate, which may have been induced by suppression of the possible photoisomerization of squaraines. In accordance with the finding of non-radiative decay, a DSSC fabricated with SQM1a exhibited a significantly enhanced short-circuit current density, which revealed an efficient electron injection derived from the double-anchored and conformationally locked structure of SQM1a. Consequently, the performance of DSSCs fabricated with SQM1a was higher than the performance of those fabricated with SQM1b and MSQ. This indicates that substantial advantages can be derived by restricting the conformation of symmetrical squaraine dyes.