Fabrication And Characterization Of CdS Quantum Dots Sensitized Transparent TiO₂ Array Photoanode

Solar cell is in many people's grace for its cleanness and non-pollution.In the paper, the develop history, current situation and existing problem of solar cell are expatiated, the structures and principles of different kinds of soalr cell are reviewed. Of which, the dye-sensitized TiO2 solar cell is expected to reduce the costs of the present soalr cell. TiO2 can only absorb the ultraviolet-light for the wide band-gap (3.2eV), which results to the low conversion efficiency. It is essential to sensitize it. Then, the assumption of CdS quantum dots sensitized TiO2 nanotube arrays film solar cell is plotted out. Firstly, the transparent TiO2 nanoubes array electrode on the ITO glass is fabricated, and then the CdS quantum dots are deposited on the electrode by successive ionic layer adsorption and reaction (SILAR) technique. Lastly the solar cell is assembled by use of the electrode as anode. The main contents and the resultes are listed as follow:(1) The titanium film with good quantity is deposited on the ITO glass by megnetron sputtering, and then the transparent TiO2 nanotubes array film is prepared by anodizing titanium films in the ethylene glycol (EG) electrolyte solution containing NH4F and annealing. The results show that:The optical deposition parameters is that:the substrate temperature is kept at 300℃, The base chamber pressure is below 3.0×10-3Pa. The argon gas pressure is 0.5 Pa during deposition. The sputtering power is 150 W. The length, inner diameter and wall thickness of the TiO2 nanotubes array, which is fabricated in the (EG) solution containing 0.3wt% NH4F, 1vol% H2O, at 40 V anodizing potential and annealing at 450℃for 2 h, are around 1.6μm,90 nm and 20 nm respectively.(2) The sensitization of the TiO2 nanotube array by CdS quantum dots is performed by successive ionic layer adsorption and reaction (SILAR) technique, which the Cd(NO3)2, Na2S are used as the ion resources in different solvents. The results show that:the deposited CdS quantum dots by using the ethylalcohol and methanol as the solvent are more than the water, and the size of CdS quantum dots is 5-10nm and the crystalline orientation at (110). After 4 cycle deposition, the performance of the CdS quantum dots sensitized TiO2 nanotubes array is best.