Published online by Cambridge University Press: 23 January 2014
Nb, F-codoped TiO2 (NFT) nanoparticles are prepared via hydrothermal processes using Nb2O5 and hydrofluoric acid as doping source. Nb and F distribute homogeneously in the NFT nanoparticles as shown in scanning transmission electron microscopy elemental mappings. The codoping of Nb and F improves the crystallinity of TiO2 significantly and increases the Ti3+ concentration, which results in the enhancement of electron injection and in the increase of the charge-transfer ability in dye-sensitized solar cells. The relative energy conversion efficiency can be 66.1% higher than that of the cell, based on pure TiO2, when the Nb:F:Ti molar ratio is about 0.03:0.15:0.97.