Controllable Preparation Of Quantum Dot Sensitized TiO₂Nanorod Arrays And Their Photoelectric Properties

Inorganic semiconductor quantum dots (QDs) are considered the potential sensitizer for the nanocrystalline sensitized solar cell due to its advantages of adjustable band gap, high extinction coefficient, multi-exciton effects, ease of synthesis and low preparation cost. Meanwhile, TiO2nanorods arrays with high orderly structure and the efficient electron transport were expected to replace the traditional TiO2nanocrystalline as the photoanode materials. In this work, TiO2nanorod arrays were prepared by the hydrothermal method on the transparent conductive glass substrate. The influence of process parameters on the array morphology was investigated. By using the successive ionic layer adsorption and reaction (SILAR) process, CdS and CdSe QDs were grown on the TiO2nanorod arrays. Using chemical bath deposition (CBD) method, the Sb2S3QDs were deposited on the surface of TiO2nanorod arrays. The quantum dots sensitized solar cells by using the QDs sensitized TiO2nanorod arrays were also prepared and characterized. The main results are as follows:1. The preparation process of TiO2nanorod array:In acidic conditions, with Ti(OBu)4and HCl solution were used as the former solution, TiO2nanorod arrays were prepared on the FTO substrate in the temperature range of130-200℃, time range of5-20h. XRD and TEM results showed the TiO2nanorods were rutile phase. SEM images indicated that the length and diameter of the nanorod increases with the increasing of the concentration, temperature and time. The optimal parameters are170℃,10h and0.8g/100ml.2. CdS、CdSe QDss were prepared in the way of successive ionic layer adsorption and reaction (SILAR) process. Cd (NO3)2and Na2S were used as Cd2+, S2+sources, Na2Se and Cd (NO3)2were used as Se2-、Cd2+sources. The results indicates that CdS QDs extended the absorption edge to550nm, CdSe QDS can extended the absorption edge to about700nm and Sb2S3QDs extended the absorption edge to650nm, which corresponding to the band gap of the CdS, CdSe and Sb2S3, respectively.3. The solar cells were prepared by using the QDs sensitized TiO2nanorod arrays as the photoanodes. The Ⅰ-Ⅴ characterization results shows that the maximum efficiency of the CdS, CdSe and Sb2S3QDs sensitized solar cells was0.69%,0.39%and0.12%, respectively. While the CdS/CdSe QDs cosensitized solar cells exhibited the higher efficiency with1.34%.