SiW12、PbS对提高TiO2纳米管光电转换效率的协同效应研究

复合薄膜可以改善TiO2纳米管在光电转换时电子-空穴易复合和吸收光谱范围窄的缺陷。用电沉积法将多酸H4SiW12O40（SiW12）沉积在TiO2纳米管表面形成SiW12/TiO2纳米管复合薄膜，再用连续离子层吸附反应法（SILAR）将PbS吸附到SiW12 /TiO2纳米管复合薄膜表面，形成PbS/ SiW12/TiO2纳米管复合薄膜，所得薄膜的光电转换效率相较于TiO2纳米管提高了57倍。X射线衍射（XRD）和扫描电子显微镜（SEM）表征结果表明，用电沉积法和连续离子层吸附反应法实现了PbS/SiW12/TiO2纳米管复合薄膜的制备；紫外可见（UV-vis）吸收光谱测试表明，复合薄膜的光吸收带边扩展到了可见光区域，电化学阻抗测试（EIS）表明，复合薄膜具有更高的电子转移速率；荧光光谱（PL）测试表明，复合薄膜拥有更小的电子-空穴复合率。以上结果说明，SiW12、PbS与TiO2纳米管复合，很好地抑制了TiO2纳米管电子-空穴的复合，并拓宽了吸收光谱范围，能显著地提高TiO2纳米管的光电性能。本文探索了一种有效提高TiO2纳米管光电转换效率的方法，对TiO2纳米管复合薄膜的制备具有一定的参考意义。

Study on SiW12 cooperating with PbS to improve the photoelectric conversion efficiency of TiO2 nanotube

The composite films can improve the defects of easy electron-hole recombination and narrow absorption spectrum of TiO2 nanotubes during photoelectric conversion. The polyoxometalates H4SiW12O40 (SiW12) was deposited on the surface of TiO2 nanotubes by electrodeposition to form SiW12/TiO2 nanotube composite films, and then PbS were adsorbed to SiW12/TiO2 nanotube composite films by continuous ionic layer adsorption reaction method (SILAR) to form SiW12/TiO2 nanotube composite films, and the photoelectric conversion efficiency of the obtained films was 57 times higher than TiO2 nanotubes. The characterization results of X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that the preparation of PbS/SiW12/TiO2 nanotube composite films was realized by electrodeposition and SILAR. Ultraviolet-visible (UV-vis) absorption spectroscopy test showed that the light absorption band edge of the composite films was extended into the visible region. Electrochemical impedance spectroscopy (EIS) test showed that the composite films had a higher electron transfer rate. Fluorescence spectroscopy (PL) test showed that the composite films had a smaller electron-hole recombination rate. The above results indicate that the combination of SiW12 and PbS with TiO2 nanotubes can well inhibit the electron-hole recombination of TiO2 nanotubes and broaden the absorption spectrum, which can significantly improve the photoelectric properties of TiO2 nanotubes. In this paper, a method to effectively improve the photoelectric conversion efficiency of TiO2 nanotubes was explored, which has certain reference significance for the preparation of TiO2 nanotube composite films.