CdS/TiO2纳米棒阵列复合材料的制备及其光电化学特性

以水热法在氟掺杂的氧化锡透明导电玻璃(FTO)上制备的TiO₂纳米棒阵列为衬底, 通过连续化学水浴沉积(S-CBD)法将CdS量子点 (QDs)沉积在TiO₂纳米棒上, 形成CdS/TiO₂阵列复合材料。分别利用高分辨透射电子显微镜(HRTEM)、 场发射扫描电子显微镜(FESEM)、 X射线衍射(XRD)和紫外可见光谱(UV-vis)等对样品的形貌、 晶型以及光吸收性能进行了表征。结果表明, TiO₂纳米棒阵列长度约为2.9 μm, CdS QDs的尺寸大约在5~9 nm。随着沉积层数的增加, CdS QDs的厚度增加, 同时伴随着光吸收边的红移。通过电流-电压特性曲线对其光电流-电压特性进行了分析, 发现光电流和光电转换效率均呈现出先增大后减小的规律。100 mW/cm²的光照下, 在S-CBD为7层时, 光电流和开路电压最大值分别达到2.49 mA·cm^-2和1.10 V, 而电池的效率达到最大值1.91%。

Preparation and photoelectric characteristics of CdS/TiO2 compound nanoarray

TiO₂ nanorod arrays film was prepared on FTO by a simple hydrothermal synthesizing method. The formation of CdS quantum dots (QDs) sensitized TiO₂ nanorods was carried out by sequential chemical bath deposition (S-CBD) technique. The morphologies, phase structure, and optical absorption properties of the as-prepared materials were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and UV-vis spectrometer. The results indicate that the length of TiO₂ nanorods array is up to 2.9 μm and the diameters of CdS quantum dots range from 5 nm to 9 nm. With the increase of the sedimentary layers, the thickness of the CdS QDs increases, accompanied by the red shift of the absorption edge. By analyzing the photocurrent-voltage characteristics from I-V curve, it can be found that the photocurrent and photoelectric conversion efficiency both increase first and then decrease. A photocurrent of 2.49 mA·cm^-2, an open circuit photovoltage of 1.10 V, and a conversion efficiency of 1.91% are obtained under an illumination of 100 mW/cm², when the CdS QDs deposites on TiO₂ nanorod arrays film for about 7 cycles.