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The effects of the crystal nature on the luminescent emission of Eu 3+ ion in Y 2 O 3 , HfO 2 and ZrO 2 oxides, synthesized by the hydrothermal route are reported. The luminescent spectra at room temperature, showed the peaks associated with the characteristic transitions of Eu 3+ ion, observing significant changes in the electric dipole transition 5 D 0 → 7 F 1 (D°→D 1 ), in each of the different crystals; the analysis by group theory allowed us to offer an explanation of the differences presented in the emission spectra in the different crystals. [ABSTRACT FROM AUTHOR]

ZrO 2 , ZrO 2 :Dy 3+ and ZrO 2 :Dy 3+ , Gd 3+ films were synthesized using the Pyrosol technique. These films have a ZrO 2 -metastable tetragonal crystalline structure, which is better defined as the deposition temperature increases. Photoluminescence and cathodoluminescence properties of these films were studied as a function of deposition parameters such as substrate temperature and Dy 3+ and Gd 3+ relative concentrations. All luminescent emission spectra showed the typical electronic transitions 4f → 4f of the Dy 3+ ions at 480, 574 and 655 nm. The luminescent intensity is observed to increase with the Dy 3+ ion concentration up to 7 at.% in the spraying solution (1.8 at.% inside films), higher concentration result in an inhibition of the luminescence. Incorporation of Gd 3+ ions in ZrO 2 :Dy 3+ films produced a marked increase in the luminescent emission intensity (approximately 15 times). The elemental composition and surface morphology of these films are also reported. [ABSTRACT FROM AUTHOR]

Trivalent erbium doped zirconium oxide films were deposited by the ultrasonic spray pyrolysis technique. Films were deposited using zirconium tetrachloride octahydrate (ZrCl4O·8H2O) and erbium nitrate hexahydrate ((NO3)3Er·6H2O) as precursors and deionized water as solvent. The dopant concentrations in the spray solution were 1, 3, 5, 10 and 15at% in ratio to zirconium content. The films were deposited on corning glass substrates at different temperatures from 400 up to 550°C. Films deposited at temperatures lower than 400°C were amorphous, however, as substrate temperatures are increased, the ZrO2 films presented a better crystallinity and showed a tetragonal phase. Cathodoluminescence (CL) emission spectra showed bands centred at 524, 544 and 655nm associated with the electronic transition of Er3+. [ABSTRACT FROM AUTHOR]

This paper reports the luminescent response upconversion of zirconium oxide (ZrO 2 ) nanoparticles doped with erbium (Er 3+ ) and ytterbium (Yb 3+ ) ions, synthesized by hydrothermal route. X ray diffraction (DRX) showed that the synthesized material presents the face centered cubic (FCC) structure. High resolution transmission electron microscopy (HRTEM) showed the presence of crystals size smaller than 10 nm. The photoluminescent analysis allowed to observe an intense upconversion luminescence emission of the samples doped with both ions Er 3+ and Yb 3+ , when these are excited with 910 nm laser source, showing the electronic transitions 4 F 9/2 → 4 I 5/2 ; 2 H 11/2 → 4 I 5/2 ; 4 S 3/2 → 4 I 15/2 of Er 3+ . Two decay times were observed, whose behavior can be associated to the average distance between erbium ions within the nanocrystals. [ABSTRACT FROM AUTHOR]

ZrO 2 :Dy 3+ and ZrO 2 :Dy 3+ + x Li + films were synthesized by an ultrasonic spray pyrolysis process. X-Ray Diffraction studies, as a function of the deposition temperature, indicate a meta-stable tetragonal crystal structure of the zirconia, as the substrate temperature was increased. Photoluminescence and cathodoluminescence characteristics of the films were studied as a function of deposition parameters such as the substrate temperature and the dysprosium and lithium concentrations. For an excitation wavelength of 286 nm, all the luminescent emission spectra show peaks located at 485, 584, 670 and 760 nm, which are the characteristic 4f→4f intra-transitions of Dy 3+ ions and they correspond to electronic transitions 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 13/2 , 4 F 9/2 → 6 H 11/2 and 4 F 9/2 → 6 H 9/2 , respectively. The lithium incorporation in the ZrO 2 :Dy 3+ films produced an improvement in the intensity of the luminescent emission. As the deposition temperature is increased, a rise of the luminescence intensity is observed. Also, it is noted, a quenching of the luminescence, with increasing doping concentration. The elemental chemical composition of the layers, as determined by energy dispersive spectroscopy, is reported as well. In addition, the surface morphology characteristics of the films, as a function of the deposition temperature, are presented. [ABSTRACT FROM AUTHOR]

ZrO 2 :Dy 3+ and ZrO 2 :Dy 3+ + x Li + films were synthesized by an ultrasonic spray pyrolysis process. X-Ray Diffraction studies, as a function of the deposition temperature, indicate a meta-stable tetragonal crystal structure of the zirconia, as the substrate temperature was increased. Photoluminescence and cathodoluminescence characteristics of the films were studied as a function of deposition parameters such as the substrate temperature and the dysprosium and lithium concentrations. For an excitation wavelength of 286 nm, all the luminescent emission spectra show peaks located at 485, 584, 670 and 760 nm, which are the characteristic 4f→4f intra-transitions of Dy 3+ ions and they correspond to electronic transitions 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 13/2 , 4 F 9/2 → 6 H 11/2 and 4 F 9/2 → 6 H 9/2 , respectively. The lithium incorporation in the ZrO 2 :Dy 3+ films produced an improvement in the intensity of the luminescent emission. As the deposition temperature is increased, a rise of the luminescence intensity is observed. Also, it is noted, a quenching of the luminescence, with increasing doping concentration. The elemental chemical composition of the layers, as determined by energy dispersive spectroscopy, is reported as well. In addition, the surface morphology characteristics of the films, as a function of the deposition temperature, are presented. [ABSTRACT FROM AUTHOR]