Multisite luminescence of rare earth doped TiO2 anatase nanoparticles

• DOI: 10.1016/j.matchemphys.2012.06.016
• Publication Date: 2012-06-30T21:00:39Z
• Authors: Željka Antić; Radenka M. Krsman...; Marko G. Nikolić; Milena Marinović-...; Miodrag Mitrić; Stefano Polizzi; Miroslav D. Drami...
• Keywords: Photoluminescence spectroscopy; Optical properties; Optical materials; 02 engineering and technology; 0210 nano-technology; Nanostructures; Optical materials; Optical properties; Photoluminescence spectroscopy;; Nanostructures

Abstract Eu 3+ , Sm 3+ and Tb 3+ ions have been incorporated into anatase TiO 2 nanocrystals via hydrolytic sol–gel method. Pure anatase phase was confirmed with XRD and TEM measurements. Band gap energies change slightly with rare earth incorporation, from 3.32 eV for undoped TiO 2 to 3.15 eV, 3.25 eV and 3.29 eV for Tb 3+ , Sm 3+ and Eu 3+ doped TiO 2 . Photoluminescence of Eu 3+ and Sm 3+ originated from three different sites in TiO 2 nanocrystals have been identified with the laser-excited site-selective spectroscopy measurements at 10 K. One site exhibits broad emission peaks, which are ascribed to the distorted lattice site near the surface. Other two sites, associated with the inner lattice, show significantly sharper fluorescence lines as a consequence of an ordered crystalline environment. The emission decays of Eu 3+ and Sm 3+ have similar values for inner-lattice sites and longer lifetimes for near-surface sites. The luminescence of Tb 3+ doped TiO 2 nanocrystals was immeasurably weak.