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Research paper thumbnail of Synthesis and characterization of Gd 2O 3:Eu 3+ phosphor nanoparticles by a sol-lyophilization technique

Journal of Solid State Chemistry, 2003

The characterization and luminescence properties of nanostructured Gd 2 O 3 :Eu 3+ phosphors synt... more The characterization and luminescence properties of nanostructured Gd 2 O 3 :Eu 3+ phosphors synthesized by a sol-lyophilization process are presented. After preparation of gadolinium-based sols from gadolinium nitrate and ammonium hydroxide, the soprepared sols were freeze dried at À101C and calcinated at different temperatures. For temperatures lower than 1300 K, highly crystalline samples with the cubic structure can be obtained without concomitant grain growth of the particles (o50 nm). The luminescence spectra contain all possible transitions of Eu 3+ with C 2 symmetry and present two major features: an increase of the luminescence efficiencies of the phosphors in comparison with that obtained by solid-state reaction and the presence of an additional peak at about 609 nm at the vicinity of the 5 D 0 -7 F 0y4 transition. r

Research paper thumbnail of Synthesis and properties of europium-based phosphors on the nanometer scale: Eu 2O 3, Gd 2O 3:Eu, and Y 2O 3:Eu

Journal of Colloid and Interface Science, 2004

Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE 2... more Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE 2 O 3 (RE = Y, Gd) have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by high-resolution TEM, absorption spectroscopy, and luminescence spectroscopy. The samples obtained consisted of concentrated and colloidally stable suspensions of luminescent oxide nanoparticles with an average grain diameter in the range 2-5 nm. The nanoparticles were found to be highly crystalline despite their ultrasmall size and the low temperature of 180 • C applied during the synthesis. Upon UV excitation, the red luminescence relative to the 5 D 0 → 7 F n transition within the cubic form of RE 2 O 3 exhibits some important differences from that usually found in bulk materials.

Research paper thumbnail of Synthesis and characterization of Gd 2O 3:Eu 3+ phosphor nanoparticles by a sol-lyophilization technique

Journal of Solid State Chemistry, 2003

The characterization and luminescence properties of nanostructured Gd 2 O 3 :Eu 3+ phosphors synt... more The characterization and luminescence properties of nanostructured Gd 2 O 3 :Eu 3+ phosphors synthesized by a sol-lyophilization process are presented. After preparation of gadolinium-based sols from gadolinium nitrate and ammonium hydroxide, the soprepared sols were freeze dried at À101C and calcinated at different temperatures. For temperatures lower than 1300 K, highly crystalline samples with the cubic structure can be obtained without concomitant grain growth of the particles (o50 nm). The luminescence spectra contain all possible transitions of Eu 3+ with C 2 symmetry and present two major features: an increase of the luminescence efficiencies of the phosphors in comparison with that obtained by solid-state reaction and the presence of an additional peak at about 609 nm at the vicinity of the 5 D 0 -7 F 0y4 transition. r

Research paper thumbnail of Synthesis and properties of europium-based phosphors on the nanometer scale: Eu 2O 3, Gd 2O 3:Eu, and Y 2O 3:Eu

Journal of Colloid and Interface Science, 2004

Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE 2... more Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE 2 O 3 (RE = Y, Gd) have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by high-resolution TEM, absorption spectroscopy, and luminescence spectroscopy. The samples obtained consisted of concentrated and colloidally stable suspensions of luminescent oxide nanoparticles with an average grain diameter in the range 2-5 nm. The nanoparticles were found to be highly crystalline despite their ultrasmall size and the low temperature of 180 • C applied during the synthesis. Upon UV excitation, the red luminescence relative to the 5 D 0 → 7 F n transition within the cubic form of RE 2 O 3 exhibits some important differences from that usually found in bulk materials.

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