Synthesis, XPS and luminescence (investigations) of Li+ and/or Y3+ doped nanosized titanium oxide

Nanoparticles of titanium dioxide co-doped with Y3+ and Li+ were prepared using the sol–gel method and were characterized by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. According to the XPS results co-doping TiO2 with Y3+ and Li+ seems to help to homogenize the distribution of dopants in the particle bulk since both Y and Li relative amounts at surface decrease compared to the Y3+ or Li+ doped TiO2. At 800 °C rutile is the only observed phase for the undoped and (Li+, Y3+) co-doped samples. However, the diffractogram of Li+ doped TiO2 shows additional peaks relative to the Li4Ti5O12 phase. Traces of Y2Ti2O7 and anatase are identified for the Y3+ doped titania. Luminescence studies show that Li+ induced an important and long lived luminescence emission in the millisecond time range, peaking at 724 nm which is reported here for the first time. The signal was more itense when samples were annealed at 800 °C. An increase of the Li+ and Y3+ to 7% or 10% produced an increase in the intensity of the emission.