Facile preparation carbon-doped TiO2 nanotube electrodes and its enhanced photoelectrochemical response

Abstract

Nanostructured carbon-doped titanium dioxide were fabricated by thermal treatment of anodized titanium dioxide nanotube with the presence of NaHCO3. The resulted samples were characterized via X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra, electrochemical impedance spectroscopy and photoelectrochemistry methods. Anatase type TiO2 nanotubes and almost no influence from C doping were observed from XRD and SEM results. XPS spectra showed that the O was partly replaced by C in the resulted carbon-doped titanium dioxide nanotubes. Enhanced photocurrents were identified for the C-TiO2 nanotube and 1.7 times was observed in comparison to the TiO2. Electrochemical impedance spectroscopy indicates the decrease of charge transfer resistance and flat band potential also negative shift from -0.28 V to -0.38 V. Needle- shaped dye sensitized solar cells were developed by using anodized Ti and Pt wire. Improved photovoltaic performance was demonstrated by the photocurrent density-photovoltage curves for DSSCs when the anodized Ti wire was thermal treated with the presence of NaHCO3. The short-circuit current and energy conversion efficiency were up to 0.17 mA/cm2 and 3.8%, respectively.