SiW_(12)、PbS对提高TiO_(2)纳米管光电转换效率的协同效应

Study on SiW_(12) Cooperating with PbS to Improve the Photoelectric Conversion Efficiency of TiO_(2) Nanotube

复合薄膜可以改善TiO_(2)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H_(4)SiW_(12)O_(40)(SiW_(12))沉积在TiO_(2)纳米管表面形成SiW_(12)/TiO_(2)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SiW_(12)/TiO_(2)纳米管复合薄膜表面,形成PbS/SiW_(12)/TiO_(2)纳米管复合薄膜,所得薄膜的光电转换效率相较TiO_(2)纳米管提高了57倍。X射线衍射和扫描电镜表征结果表明,用电沉积法和连续离子层吸附反应法实现了PbS/SiW_(12)/TiO_(2)纳米管复合薄膜的制备;紫外可见吸收光谱测试表明,复合薄膜的光吸收带边扩展到了可见光区域;电化学阻抗测试表明,复合薄膜具有更高的电子转移速率;荧光光谱测试表明,复合薄膜拥有更小的电子⁃空穴复合率。以上结果说明,SiW_(12)、PbS与TiO_(2)纳米管复合,很好地抑制了TiO_(2)纳米管电子⁃空穴的复合,并拓宽了吸收光谱范围,能显著提高TiO_(2)纳米管的光电性能。

The composite films can improve the defects of easy electron⁃hole recombination and narrow absorption spectrum of TiO_(2) nanotubes during photoelectric conversion.The polyoxometalates H_(4)SiW_(12)O_(40)(SiW_(12)) was deposited on the surface of TiO_(2) nanotubes by electrodeposition to form SiW_(12)/TiO_(2) nanotube composite films,and then PbS were adsorbed to SiW_(12)/TiO_(2)nanotube composite films by continuous ionic layer adsorption reaction method(SILAR)to form PbS/SiW_(12)/TiO_(2)nanotube composite films,and the photoelectric conversion efficiency of the obtained films was 57 times higher than that of TiO_(2) nanotubes.The characterization results of XRD and SEM showed that the preparation of PbS/SiW_(12)/TiO_(2) nanotube composite films was realized by electrodeposition and SILAR.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 test showed that the composite films had a higher electron transfer rate.Fluorescence spectroscopy test showed that the composite films had a smaller electron⁃hole recombination rate.The above results indicate that the combination of SiW_(12) and PbS with TiO_(2) nanotubes can well inhibit the electron⁃hole recombination of TiO_(2) nanotubes and broaden the absorption spectrum,which can significantly improve the photoelectric properties of TiO_(2) nanotubes.