CdS/PbS量子点共敏化三维结构TiO_2纳米管阵列光电极的制备及其光电化学性能表征

Fabrication and Photoelectrochemical Performance of CdS/PbS Quantum Dots Cosensitized 3D TiO_2 Nanotube-Array Photoelectrodes

通过阳极氧化法在钛丝网基底上制备出三维结构的TiO2纳米管阵列。采用连续离子层吸附与反应法制备了CdS、PbS、CdS/PbS量子点(QDs)敏化TiO2纳米管阵列光电极。利用X射线衍射仪、扫描电子显微镜、能谱定量分析、高分辨透射电镜、紫外–可见漫反射光谱对其形貌和结构进行了表征。结果表明:CdS、PbS量子点成功沉积在TiO2纳米管阵列上,QDs/TiO2纳米管阵列具有比纯TiO2纳米管阵列更好的可见光吸收性能。使用电化学工作站测试光电极材料的光电化学性能,结果表明:QDs/TiO2纳米管阵列具有良好的可见光响应性和稳定性;在100mW/cm2氙灯光照下,CdS/PbS/TiO2光电极具有最高的光电流密度,为5.86mA/cm2,分别是单一量子点敏化CdS/TiO2、PbS/TiO2光电极的3.35、1.21倍。对比在钛片基底上的二维结构TiO2纳米管阵列,三维结构纳米管阵列的光电流随入射光角度增大而衰减的缺点得到极大改善,这对其在太阳能电池中的实际应用有重要意义。

The 3D TiO2 nanotube arrays were prepared via anodization on titanium mesh. The CdS, PbS and CdS/PbS quantum dots （QDs） sensitized TiO2 nanotube arrays were fabricated by successive ionic layer adsorption and reaction method. The samples were characterized by X-ray diffraction technique, scanning electron microscopy, energy-dispersive spectrometry, high-resolution transmission electron microscopy, and UV-visible diffuse reflectance spectroscopy, respectively. The results show that CdS and PbS quantum dots are deposited onto TiO2 nanotubes. The QDs/TiO2 nanotube arrays exhibit improvements on visible-light absorption properties. The photoelectrochemical performance of the photoelectrodes was investigated by means of an electrochemical work station. Under visible-light illumination with an intensity of 100 mW/cm2, the photocurrent density obtained by CdS/PbS/TiO2 photoelectrode is 5.86 mA/cm2, which is 3.35 and 1.21 times of those by CdS/TiO2 and PbS/TiO2 photoelectrodes, respectively. Compared to TiO2 nanotube arrays on Ti sheet, the photocurrent reduction of TiO2/Ti meshes with increasing illumination angles is improved for promising applications in solar cells.