Influence of titanium and lutetium on the persistent luminescence of ZrO2

Non-doped as well as titanium and lutetium doped zirconia (ZrO2) materials were synthesized via the sol-gel method and structurally characterized with X-ray powder diffraction. The addition of Ti in the zirconia lattice does not change the crystalline structure whilst the Lu doping introduces a small fraction of the tetragonal phase. The UV excitation results in a bright white-blue luminescence at ca. 500 nm for all the materials which emission could be assigned to the Ti3+ e(g) -> t(2g) transition. The persistent luminescence originates from the same Ti3+ center. The thermoluminescence data shows a well-defined though rather similar defect structures for all the zirconia materials. The kinetics of persistent luminescence was probed with the isothermal decay curve analyses which indicated significant retrapping. The short duration of persistent luminescence was attributed to the quasi-continuum distribution of the traps and to the possibility of shallow traps even below the room temperature. (C) 2012 Optical Society of AmericaConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, Brazil)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), BrazilAcademy of FinlandAcademy of FinlandCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), BrazilCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP, Brazil)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), BrazilNanobiotecBrasil RHINAMI and inctINAMI, BrazilNanobiotec-Brasil - RH-INAMI and inct-INAMI, BrazilEuropean Community [RII3-CT-2004-506008 (IA-SFS)]European Communit