Enhanced photocurrent of nitrogen-doped TiO2 film for dye-sensitized solar cells

Nitrogen (n)-doped titanium dioxide (TiO2) was prepared with varying doping extent by a general sot-gel process with a pure TiO2 film as the control sample. The n-doped-2 electrode showed the maximum conversion efficiency with an open-circuit voltage (V-oc) of 0.726V, a photocurrent (J(sc)) of 10.52 mA cm(-2), a fill factor of 63.6%, and an efficiency of 4.86%, compared to 0.751 V, 7.4 mA cm(-2), 67.1%, and 3.73%, respectively, for the undoped (u-doped) TiO2 electrode. The approximate 23% enhancement in the conversion efficiency of the n-doped-2 TiO2 electrode-based dye-sensitized solar cells (DSSCs) was mostly ascribed to the increase of light absorption in the near-vis absorbance and partially to the morphological characteristics of the n-doped TiO2 film. Additionally, the doping type of nitrogen in the TiO2 lattice was closely studied using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The relation between the doping type and the electron behavior in the DSSCs was also examined. (C) 2010 Elsevier B.V. All rights reserved.