Abstract
In this thesis, carbon nanotubes (CNTs) were incorporated into TiO2 electrodes and the corresponding changes in photo-conversion efficiency were studied. Experiments were carried out using single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) and results were compared. CNTs were firstly treated by acids and subsequently added into pre-prepared porous TiO2 nanoparticle film using doctor-blade method. The CNT-incorporated TiO2 electrodes were then sintered in air or nitrogen. Raman spectroscopy and FE-SEM were employed to examine the existence of CNTs in the electrodes, and UV-vis spectrophotometry was used to determine the amount of dye molecules adsorbed on the electrodes. We found that, with CNTs addition, the absorption of dye molecules and the photo-conversion efficiency of the TiO2 electrodes can be enhanced to certain extents. Nevertheless, excess of CNTs would decrease the absorption of dye molecules, thereby resulting in reduction of the energy-conversion efficiency. We also carried out the photoluminescence spectroscopy and photocatalytic oxidation experiments, and the results confirmed that CNTs addition do help to slow down the rate of electron-hole pair recombination.