Anionic ligand assisted synthesis of 3-D hollow TiO2 architecture with enhanced photoelectrochemical performance.
Anionic ligand assisted synthesis of 3-D hollow TiO2 architecture with enhanced photoelectrochemical performance.
复制标题
DOI：
10.1021/la503641n
复制
发表时间：
2014-12
期刊：
影响因子：
--
通讯作者：
Seong Sik Shin;Dong Wook Kim;Jong Hoon Park;Dong Hoe Kim;Ju Seong Kim;K. Hong;I. Cho
中科院分区：
文献类型：
--
作者：
Seong Sik Shin;Dong Wook Kim;Jong Hoon Park;Dong Hoe Kim;Ju Seong Kim;K. Hong;I. Cho
中空结构材料在光电化学器件中的应用显示出巨大的优势。然而，它们糟糕的电荷传输限制了设备的整体性能。在这里，我们报道了一种独特的三维中空结构的二氧化钛，它极大地改善了电荷传输特性。我们发现柠檬酸(CA)在三维中空结构的形成中起着至关重要的作用。首先，在水热合成过程中，CA控制了钛离子的水解速度，促进了模板表面的水解。其次，CA在反应初期抑制了碳模板的生长，形成了相对较小的中空纤维。更重要的是，与CA的长期水热反应使中空球能够通过仿生吞噬生长而生长成缠绕的中空纤维。为了展示三维空心结构光电化学器件的优势，我们以染料敏化太阳能电池为模型器件，对其光电化学性能，特别是电解液扩散和电子动力学进行了评价。系统的分析表明，与纳米颗粒和空心球相比，三维空心结构大大改善了电解液的扩散和电子的传输，这是因为纳米颗粒和空心球具有细长的多孔中空形态以及壁层上紧密相连的纳米颗粒。
Hollow structured materials have shown great advantages for use in photoelectrochemical devices. However, their poor charge transport limits overall device performance. Here, we report a unique 3-D hollow architecture of TiO2 that greatly improves charge transport properties. We found that citric acid (CA) plays crucial roles in the formation of the 3-D hollow architecture. First, CA controls the hydrolysis rate of Ti ions and facilitates surface hydrolysis on templates during hydrothermal synthesis. Second, CA suppresses the growth of the carbon template at the initial reaction stage, resulting in the formation of comparatively small hollow fibers. More importantly, a prolonged hydrothermal reaction with CA enables a hollow sphere to grow into entangled hollow fibers via biomimetic swallowing growth. To demonstrate advantages of the 3-D hollow architecture for photoelectrochemical devices, we evaluated its photoelectrochemical performance, specifically the electrolyte diffusion and electron dynamics, by employing dye-sensitized solar cells as a model device. A systemic analysis reveals that the 3-D hollow architecture greatly improves both the electrolyte diffusion and electron transport compared to those of the nanoparticle and hollow sphere due to the elongated porous hollow morphology as well as the densely interconnected nanoparticles at the wall layer.