水热法制备TiO2-ZnO纳米棒分级结构及其光电性能研究

为了增加光电极光生电子传输通道并提高其光敏剂的负载能力,采用两步水热法制备了一种新颖的TiO_2-ZnO纳米棒分级结构。采用水热法在FTO导电玻璃基底上生长TiO_2纳米棒有序阵列膜,通过浸泡提拉在TiO_2纳米棒上包覆一层ZnO溶胶,经烧结形成ZnO种子层;再次采用水热法于TiO_2纳米棒上生长ZnO纳米棒,形成TiO_2-ZnO纳米棒分级结构,通过旋涂辅助连续离子反应分别在TiO_2纳米棒阵列和TiO_2-ZnO纳米棒分级结构中沉积光敏剂CdS纳米晶,形成CdS/TiO_2纳米棒复合膜和CdS/TiO_2-ZnO纳米分级结构复合膜。利用SEM,TEM,XRD、紫外-可见吸收光谱、瞬态光电流图谱等表征和测试手段,对样品的形貌、结构、光吸收和光电性能进行了表征和测试。结果表明,与单纯的TiO_2纳米棒阵列相比,TiO_2-ZnO分级结构可以沉积更多的CdS光敏剂,CdS/TiO_2-ZnO纳米分级结构复合膜的光吸收性能和瞬态光电流均明显优于CdS/TiO_2纳米复合薄膜。凭借优异的光电性能,TiO_2-ZnO分级结构在太阳电池光阳极材料中具有很好的应用前景。

Photoelectrochemical properties of the TiO2-ZnO nanorod hierarchical structure prepared by hydrothermal process

In order to increase the transport channels of the photogenerated electrons and enhance the photosensitizer loading ability of the electrode, a new TiO₂-ZnO nanorod hierarchical structure is prepared through two-step hydrothermal process. First, TiO₂ nanorod array is grown on the FTO conductive glass substrate by hydrothermal proess. Then, ZnO sol is coated onto the TiO₂ nanorods through dip-coating method and inverted to ZnO seed layer by sintering. Finally, the secondary ZnO nanorods are grown onto the TiO₂ nanorods by the sencond hydrothermal method to form the designed TiO₂-ZnO nanorod hierarchical structure. A spin-coating assisted successive ionic layer reaction method (SC-SILR) is used to deposit the CdS nanocrystals into the TiO₂ nanorod array and the TiO₂-ZnO nanorod hierarchical structure is used to form the CdS/TiO₂ and CdS/TiO₂-ZnO nanocomposite films. Different methods, such as SEM, TEM, XRD, UV-Vis and transient photocurrent, are employed to characterize and measure the morphologies, structures, light absorption and photoelectric conversion performance of all the samples, respectively. The results indicate that, compared with the pure TiO₂ nanorod array, the TiO₂-ZnO nanorod hierarchical structure can load more CdS photosensitizer. The light absorption properties and transient photocurrent performance of the CdS/TiO₂-ZnO nanorod hierarchical structure composite film are evidently superior to that of the CdS/TiO₂ nanocomposite films. The excellent photoelctrochemical performance of theTiO₂-ZnO hierarchical structure reveales its application prospect in photoanode material of the solar cells.