The characterization of nitrogen doped TiO2 photoanodes and its application in the dye sensitized solar cells

In this paper, nitrogen doped TiO2 photoanodes were achieved by calcining the mixture of urea and the commercial P25 nanoparticles slurry. Its application in the dye sensitized solar cells was examined. X-ray photoelectron spectroscopy indicated the N substituted the O atoms and formed N-Ti-O bonds. The optical band gap of the doped TiO2 photoanodes was reduced. From the photoelectrochemical experiments, it is known that nitrogen doping introduced new energy states above the valence band of the TiO2 photoanode, which lead to the visible light response and increased electron density. Optimized photo to electric conversion efficiency of the DSSC 6.71% is obtained with short current density (Jsc) of 14.3 mA cm(-2), open circuit voltage (Voc) of 0.669 V and fill factor (FF) of 0.706 by the nitrogen doping, compared with 5.31% of the undoped one (Jsc of 13.2 mA cm(-2), Voc of 0.638 V and FF of 0.624) at 0.99sun AM1.5, which is mainly due to the energy band structure change and partly the morphology change of the photoanode. (C) 2011 American Institute of Physics. [doi:10.1063/1.3599840]