Influence of titanium and lutetium on the persistent luminescence of ZrO_2

Abstract

Non-doped as well as titanium and lutetium doped zirconia (ZrO 2 ) 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 Ti 3+ e g  t 2g transition. The persistent luminescence originates from the same Ti 3+ 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. 1076-1078 (2000). 13. R. C. Garvie, R. H. Hannink, and R. T. Pascoe, "Ceramics steel," Nature 258(5537), 703-704 (1975)

Afterglow and thermoluminescence of ZrO2 nanopowders

“…Taking into account the differences in heating rates, only the 205°C glow peak of sample A1250 seems to coincide with the 240°C glow peak reported in Ref. [8]. Remarkably, the deconvolution methods we used produced also similar trap depth 1.16 eV for this peak whereas the Hoogenstraaten's method provides a higher value of 1.46 eV.…”

“…Recently, trap depths of 0.86, 1.02 and 1.17 eV were deduced by Carvalho et al [8] for sol-gel-derived ZrO 2 by a deconvolution of the TL glow curve recorded above room temperature (glow peaks 95, 180 and 240°C). Taking into account the differences in heating rates, only the 205°C glow peak of sample A1250 seems to coincide with the 240°C glow peak reported in Ref.…”

“…4). This may indicate that the first order kinetics model does not apply for the traps responsible for the afterglow, and a significant retrapping takes place [8].…”

“…The origin of this emission is still disputable, but is probably due to either oxygen vacancies [3][4][5], Ti impurity centres [6][7][8] or their combined aggre-gates. This PL frequently reveals an afterglow in the time frame of hundreds to thousands of seconds [4,5,[7][8][9], suggesting a perspective for implementation of new persistent phosphors. Advantages of these materials over many existing phosphors are their relatively simple structure, easier preparation (using sol-gel method), superior mechanical, chemical and thermal endurance, and non-toxicity.…”

“…A number of studies report thermoluminescence (TL) of monoclinic zirconia [4,6,8,9,[11][12][13][14], and the dosimetric use of its TL have been demonstrated [11,13,14]. Already one of the earliest works [6] suggested that oxygen vacancies act as electron traps giving rise to the TL.…”