Nanostructured Nitrogen Doping TiO Nanomaterials for Photoanodes of Dye-Sensitized Solar Cells - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 61

Fig. 3 UV-Vis absorption spectra of N-doped and undoped TiO 2 powders

Fig. 4 Various schemes illustrating the possible changes that might occur to the band gap
electronic structure of anatase TiO 2 on doping with various non-metals: a band gap of pristine
TiO 2 ; b doped-TiO 2 with localized dopant levels near the VB and the CB; c band gap narrowing
resulting from broadening of the VB; d localized dopant levels and electronic transitions to the
CB; and e electronic transitions from localized levels near the VB to their corresponding excited
states for Ti 3+ and F + centers [ 52 ]

assign the peak around 398 eV to the O-Ti-N linkages in TiO 2 lattice [ 23 ].
Therefore, we concluded that nitrogen was doped into the TiO 2 lattices by sub-
stitution at the sites of the oxygen atoms. For the Ti 2p region, the Ti 2p3/2 and Ti
2p1/2 core levels appeared at 459 and 464 eV. For the O 1s region, the binding
energies were around 530 eV. The Ti 2p and O 1s binding energies were similar to
that in the pure TiO 2 .