不同形貌TiO2薄膜的可控制备及其光电化学性能研究

采用水热法在FTO(fluorine-doped tin oxide)基底上制备不同形貌的锐钛矿结构TiO₂薄膜。通过不断增大反应前驱物中盐酸浓度,TiO₂薄膜由球状颗粒薄膜逐渐演变生长成大面积高能(001)面裸露的TiO₂纳米片阵列薄膜。通过对形貌演化规律及X射线衍射图谱变化规律进行分析,提出了不同形貌TiO₂薄膜的生长演化机制,并对盐酸在其中的作用进行了说明。为了进一步改善TiO₂薄膜的性能,采用连续离子层吸附反应法对不同形貌的TiO₂薄膜进行CdS量子点敏化。采用紫外可见吸收光谱分析法和三电极体系对复合薄膜的光吸收性能和光电化学(PEC)性能进行了研究,实验数据显示CdS/TiO₂复合薄膜的光电化学性能皆明显优于单纯TiO₂薄膜,而且纳米片阵列薄膜的性能明显优于其他形貌薄膜,说明了大面积高能(001)面裸露的TiO₂纳米片阵列薄膜的性能优越性。

Controllable Preparation and Photoelectrochemical Performance of TiO2 Thin Film with Different Morphology

Anatase TiO₂ thin films with different morphology were prepared on FTO substrates by hydrothermal method. With the increasing of hydrochloric acid concentration in the precursor, TiO₂ thin films gradually evolved from spherical particle films into TiO₂ nanosheet array films with a large percentage of high-energy exposed (001) planes. By analyzing the evolution rule of morphology and X-ray diffraction patterns, a reasonable growth and evolution mechanism of TiO₂ thin film with different morphology was proposed, and the role of hydrochloric acid was explained. In order to further improve the performance of TiO₂ thin films, CdS quantum dots (QDs) sensitization was performed on different TiO₂ thin films by the successive ionic layer adsorption and reaction method. The optical absorption performance and photoelectrochemical (PEC) properties of composite films were studied by ultraviolet visible absorption spectroscopy and three-electrode electrochemistry system. The optical absorption data and PEC performance data show that the properties of CdS/TiO₂ composite films are better than those of pure TiO₂ thin films, and the properties of nanosheet array films are obviously better than other morphologies, which illustrates the performance superiority of TiO₂ nanosheet array films with large area high-energy (001) planes exposed. The excellent PEC properties also suggest that the QDs sensitized TiO₂ nanosheet array films with a large percentage of high-energy surfaces have potential applications in PEC solar cells.