CdS/TiO_2纳米棒阵列复合材料的制备及其光电化学特性

Preparation and photoelectric characteristics of CdS/TiO_2 compound nanoarray

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2.9μm,CdS QDs的尺寸大约在5～9nm。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。100mW/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2.49mA.cm-2和1.10V,而电池的效率达到最大值1.91%。

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.