No abstract

No abstract

In this work, TiO 2 nanocrystalline thin films were obtained through evaporating Ti films by electron beam deposition (EBD) followed by thermal treatment. The results show that after annealing at 300, 400 and 450 °C for 8 h, the obtained TiO 2 thin films have nanoparticle and nanorod structures of 15–30 nm diameter and 100–300 nm length. At 750 °C for 8 h, the rutile phase was formed. The incorporation of cadmium sulfide (CdS) into TiO 2 nanoparticle thin films was investigated. A CdS thin film was vacuum deposited onto the pre-deposited TiO 2 film by a thermal evaporation technique. The obtained TiO 2 and TiO 2/CdS nanocomposite films were characterized by x-ray diffraction (XRD) and a field emission scanning electron microscope (FE-SEM). The TiO 2/CdS composite film was used in a photo-electrochemical (PEC) cell as a working electrode and in a platinum electrode as a counter electrode. The electrolyte solution contains 1 M KCl and 0.1 M Na 2 S. The results show that the cell with the TiO 2/CdS composite film electrode has significantly improved photoelectric capability in comparison with that of pure TiO 2 thin films, and the best thickness of the CdS thin film deposited on the ITO/TiO 2 substrates is 70–140 nm.

Perpendicularly self-aligned TiO 2 nanotube samples of size of 3 × 5 cm 2 were fabricated by the electrochemical anodization method using a solution containing NH 4 F. Influences of the technological conditions such as NH 4 F concentration and anodization voltage were studied. It was found that NH 4 F concentration in the solution and anodization voltage significantly affect the diameter and length of a TiO 2 nanotube. The diameter and the length of a TiO 2 nanotube were observed and estimated by using scanning electron microscopy. It has shown that the largest diameter and the longest length of about 80 nm and 20 µm, respectively, were obtained for the sample anodized in a solution containing 0.4% of NH 4 F, under a voltage of 48 V. Photoluminescence spectra excited by laser lights having wavelengths of 325 and 442 nm (having energies higher and lower than the band gap energy of TiO 2 ) was recorded at room temperature for the TiO 2 nanotube arrays. An abnormal luminescence result was observed. It is experimental evidence that the manufactured TiO 2 nanotube array is an expected material for hydrogen splitting from water by photochemical effect under sunlight as well as for the nano solar cells.

No abstract