Highly ordered anodized Nb2O5 nanochannels for dye-sensitized solar cells

• For the first time, highly ordered Nb2O5 nanochannels were used in DSSCs.
• DSSCs with 10 μm films had the best performance compared with other film thicknesses.
• Thicker films decreased the electron lifetime and the charge transfer resistance.
• More embedded impurities in thicker films hindered the performance of the DSSCs.

Highly ordered anodized Nb2O5 nanochannels are synthesized and utilized as the photoanodes for dye-sensitized solar cells (DSSCs). We characterize these DSSCs to determine the optimum photoanode thickness for the best cell performance. The samples with thicknesses from 5 to 25 μm are obtained in glycerol based electrolyte at 180 °C and their photoconversion properties are investigated utilizing various techniques including photocurrent–voltage characteristic, photovoltage decay and electrochemical impedance spectroscopy. Overall, the DSSC incorporating a 10 μm thick Nb2O5 photoanode shows the highest efficiency of 4.48%. We analyze the factors that limit the efficiency of DSSCs.