Geometrical effect of stilbene on the performance of organic dye-sensitized solar cells
作者:Yan-Duo Lin、Tahsin J. Chow
DOI:10.1039/c1jm11623a
日期:——
New metal-free organic donor–bridge–acceptor dyes comprising a triphenylamine moiety as the electron donor (D), a cyanoacrylic acid moiety as the electron acceptor (A), and a conjugated chromophore between D and A as a spacer (S) were synthesized for the application of dye-sensitized solar cells (DSSCs). Two types of S were designed, one contains a normal stilbene backbone (dye 1) and the other contains a 2-phenylindene moiety (dye 2) with the central double bond locked in a transoid geometry. The performance of DSSCs made with these two types of dyes was compared, and it was found that the inhibition of trans/cis isomerization of the central double bond was advantageous to the efficiency of DSSCs. The phenomenon was investigated by a comparison of their photophysical properties, and rationalized by quantum mechanical calculations by using density functional theory (DFT) at the B3LYP/6-31G(d,p) level. The electronic transitions were analyzed by time-dependent DFT, and the results were consistent with the experimental observations. The DSSCs were fabricated using both types of materials, and the performance was recorded under AM 1.5G irradiation (100 mW cm−2) condition. The overall conversion efficiencies of dye 2 (5.14–5.67%) were higher than those of dye 1 (4.52–4.98%). Both the short-circuit photocurrent density (Jsc) and the open-circuit voltage (Voc) were improved in 2 with respect to those of 1.
新型无金属有机供体-桥接体-受体染料被合成,包含三苯胺基团作为电子供体(D),氰基丙烯酸基团作为电子受体(A),并在D和A之间配置了共轭色谱基团作为间隔体(S),用于染料敏化太阳能电池(DSSCs)的应用。设计了两种类型的S,其中一种包含正常的斯蒂尔本主链(染料1),另一种则包含带有锁定在反式几何构型的中央双键的2-苯基茚基团(染料2)。对这两种染料制成的DSSCs性能进行了比较,发现抑制中央双键的反/顺异构化有利于DSSCs的效率。通过比较它们的光物理特性来研究这一现象,并通过使用密度泛函理论(DFT)在B3LYP/6-31G(d,p)水平进行量子力学计算进行合理化。电子跃迁通过时间相关的DFT进行分析,结果与实验观察一致。使用这两种材料制造了DSSCs,并在AM 1.5G照射(100 mW cm−2)条件下记录了性能。染料2的整体光电转化效率(5.14–5.67%)高于染料1(4.52–4.98%)。相比于染料1,染料2的短路光电流密度(Jsc)和开路电压(Voc)均有所提高。