Electro-Optics and Band Gap Energies of Nanosilver-Coated TiO_2 Nanotubes on Titanium Metal

TiO₂ nanotubes on Ti metal surface were prepared by the electrochemical anodization method. Then, nanosilver was deposited onto the nanotubes by the electroless dip coating and the anodization. The obtained TiO₂ nanotubes were examined by using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, cyclic voltammetry, and UV-Vis. The electrochemical band gap (E _g ^CV ) of the nanosilver-coated TiO₂ nanotubes prepared by the anodization was found as 1.54 eV. Using the UV-Vis measurements, the optical band gap energy (E _g ^op. ) was calculated as 1.51 eV for the Ag/TiO₂ nanotubes obtained by electroless dip coating. The electrical conductivity of the TiO₂nanotubes also increased from 3.0 × 10^-4 to 34.7 S/cm after nano Ag deposition by the anodization method. These Ag/TiO₂ nanotubes with low band gap and high electrical conductivity are desirable for the applications in electronics, Li-ion batteries, and solar cells.