28th European Photovoltaic Solar Energy Conference and Exhibition; 2799-2802 The properties of TiO2–dye–electrolyte interface and the electronic structure of the junction play a key role in the performance of dye-sensitized solar cells (DSSCs). Doping of TiO2 nanostructure with Nb provides us with a powerful tool for engineering the electronic structure of TiO2 electrode. Nb-doped TiO2 mesoscopic layers were prepared using a sol–gel method followed by a hydrothermal treatment. X-ray photoelectron spectroscopy was used for characterization of the energetic structure of Nb-doped TiO2 layers. It was found that the Fermi level of TiO2 electrode shifted away from the conduction band minimum (CBM) for Nb content less than 1.5 mol% and shifted towards the CBM when the Nb content was more than 2.5 mol%. XRD measurements, SEM and TEM were used for the characterization of the structural properties of the prepared layers. The prepared Nb-doped TiO2 layers sensitized with N719 dye were used for fabrication of DSSCs. The best efficiency of 9.6% was demonstrated by DSSCs with 2.5 mol% Nb-doped TiO2.
