LAUSR

Abstract Tm3+-doped TiO2 nanocrystalline powders (in the range from 0.0 to 6 at. % of Tm3+) were synthesized by the sol-gel method at 500 °C. Structural, optical and photoluminescence properties were characterized by X-ray diffraction, transmission and scanning electron microscopy (TEM, SEM), UV–vis spectroscopy and photoluminescence spectroscopy. From XRD results all compositions show anatase structure, and the incorporation of Tm3+ promoted an increase in lattice parameters and inhibit the crystal growth. HRTEM micrographs show the presence of d-plane spacings corresponding to Tm2O3 and Tm2Ti2O7 phases for samples annealed at 500 °C. FTIR, reflectance UV–vis and photoluminescent spectra showed well defined bands ascribed to the Tm3+ f-f transition. Vacuum referred binding energy diagram and chemical shift model approach are presented to analyze the relationship between the TiO2 electronic structure and the Tm3+ f-f transition.