Department of Chemistry, Yale University, P. O. Box 208107, New Haven, CT 06520-8107, USA.
Dalton Trans. 2009 Dec 7(45):10078-85. doi: 10.1039/b908686b. Epub 2009 Sep 2.
A synergistic effect between anatase and rutile TiO2 is known, in which the addition of rutile can remarkably enhance the photocatalytic activity of anatase in the degradation of organic contaminants. In this study, mixed-phase TiO2 nanocomposites consisting of anatase and rutile nanoparticles (NPs) were prepared for use as photoanodes in dye-sensitized solar cells (DSSCs) and were characterized by using UV-vis spectroscopy, powder X-ray diffraction and scanning electron microscopy. The addition of 10-15% rutile significantly improved light harvesting and the overall solar conversion efficiency of anatase NPs in DSSCs. The underlying mechanism for the synergistic effect in DSSCs is now explored by using time-resolved terahertz spectroscopy. It is clearly demonstrated that photo-excited electrons injected into the rutile NPs can migrate to the conduction band of anatase NPs, enhancing the photocurrent and efficiency. Interfacial electron transfer from rutile to anatase, similar to that in heterogeneous photocatalysis, is proposed to account for the synergistic effect in DSSCs. Our results further suggest that the synergistic effect can be used to explain the beneficial effect of TiCl4 treatment on DSSC efficiency.
锐钛矿和金红石 TiO2 之间存在协同效应，其中添加金红石可以显著提高锐钛矿在降解有机污染物方面的光催化活性。在这项研究中，制备了由锐钛矿和金红石纳米颗粒（NPs）组成的混合相 TiO2 纳米复合材料，用作染料敏化太阳能电池（DSSC）的光阳极，并通过使用紫外可见光谱、粉末 X 射线衍射和扫描电子显微镜进行了表征。在 DSSC 中，添加 10-15%的金红石可以显著提高锐钛矿 NPs 的光捕获和整体太阳能转换效率。通过使用太赫兹时域光谱技术，现在探索了 DSSC 中协同效应的潜在机制。清楚地表明，注入金红石 NPs 的光生电子可以迁移到锐钛矿 NPs 的导带，从而增强光电流和效率。提出了从金红石到锐钛矿的界面电子转移，类似于多相光催化，以解释 DSSC 中的协同效应。我们的结果进一步表明，协同效应可用于解释 TiCl4 处理对 DSSC 效率的有益影响。
