Studies On The Preparation Of Nanostructure TiO₂Thin Film And Dye-sensitized Solar Cells

The nanostructure TiO₂thin films were prepared by sol-gel methodand the preparation of metal ion doping TiO₂were studied in this paper.Characterization of the films were grasped by using of X-ray diffractioninstrument（XRD）,cold field emission scanning electric mirror（SEM）,UV-visible light spectrometer （UV/vis）. We studied on the opticalproperties and photocatalytic activity of metal ion doping TiO₂. Finally,the TiO₂thin films were sensitized and the dye-sensitized solar cells（DSSC） were assembled skimpily.1. The uniform transparent nanostructure TiO₂thin films wereobtained on the glass substrate by sol-gel and spin-coating method, usingTi （OC4H9）₄, glacial acetic acid, deionized water and anhydrous alcoholas raw materials. Study of the annealing temperature showed that thematerial appeared the rutile phase after annealing temperature reached700℃in the air. The higher the annealing temperature was, the morerutile content there was. It came to the annealed temperature at900℃,diameter of rutile grain was about38.572nm. By the photocatalyticactivity, we founded when the annealing temperature was600℃, thephotocatalytic properties seemed best.2. The nano-TiO₂thin films were prepared with the same method byspin-coating process. We could study the film properties by way of thedifferent water bath time, the coating layers, the band gap and otherfactors. XRD analysis showed that the materials are anatase. Theanalysis shows that the transmittance of the films decreased graduallywith the increase of coating layers at the condition of the same waterbath; the transmission increased gradually with the increase of the waterbath time at the condition of the same number of layers. Scanning electron microscopy results showed that the sample average size reachedthe range of200～300nm. The optical band gap were calculated, whichindicated that the annealing temperature and coating layers had an effectto band gap, the higher the annealing temperature, the greater the bandgap; the more layers, the smaller band gap.3. The results of Fe³⁺doping TiO₂thin films showed that theparticle size becomes smaller with increasing the doping concentration,the grain size were about25-30nm. When preparation of sol with theaddition of Polyethylene glycol（PEG） and processing water bathtemperature between75℃～80℃, we founded that Fe³⁺dopingconcentration was0.075%, iron-doped made the absorption peak havered shift. In the photocatalytic experiments, the effect of dopingconcentration of0.075%Fe³⁺was best.4. The Rhodamine B was used to sensitize Nano-TiO₂thin films.The positive electrode was got by sensitization. DSSC can be obtainedby coupled with the counter electrode of graphite prepared afterdropping electrolyte. The results showed that Rhodamine-B improves thepure TiO₂thin films absorbance in the visible range of wavelength from375nm to700nm, and improves the iron-doped TiO₂thin films in thevisible region the wavelength from350nm to600nm. Iron dopedexpanded the sensitized spectral region and enhanced absorption effect.In the DSSC cells experiment, an area of3.8cm×1.6cm, the open circuitvoltage reached to202mV. The solar cells were assembled withiron-doped TiO₂thin films, the open circuit voltage reached to170mVwith an area of2.8cm×1.6cm.