The nanopowders of SnO2 doped with different Eu^3＋ concentrations were synthesized using the modified Pechini method. The Eu^3＋ concentrations were high above solubility limit. The average size of crystallites was c...The nanopowders of SnO2 doped with different Eu^3＋ concentrations were synthesized using the modified Pechini method. The Eu^3＋ concentrations were high above solubility limit. The average size of crystallites was controlled by the sintering temperatures. The structure and the morphology of obtained powders were examined using the XRD （X-ray diffraction） and TEM （transmission electron microscopy） analyses. The Eu2Sn2O7 phase separation was observed at relatively high concentration of Eu^3＋ ions. The ZnS：Ag micropowders were mixed with the Eu^3＋：SnO2 powders and their normalized emission was used to measure a relative efficiency of Eu3＋：SnO〉 The photoluminescence spectra of mixed powders were measured in function of Eu^3＋ concentration and average size of nanocrystallites. The reference peak method was used for comparison of intensities of the samples and selection of optimal one. The influence of the average grain size and Eu^3＋ concentration on the phosphor＇s efficiency was discussed. The presented results confirmed the rightness of synthesis of the Eu^3＋：SnO2 in form of nanocrystalites with relatively high Eu^3＋ concentration.展开更多
Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^...Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^-3 mol/L in a water solution containing relatively high, three molar concentration of urea ensured the optimal conditions for the reproducible preparation of uniform and small spherical particles. During sulfuration step elemental sulfur was mixed with precursor which eliminated necessity of using an auxiliary furnace and provided sulfur-reach reaction atmosphere. Such optimized protocol afforded synthesis of spherical and non-agglomerated nanoparticles with diameter smaller than 100 nm. The precursors morphology was maintained, but particles size was reduced by 15%-20% during sulfuration. The results indicated that higher emission intensity was observed for Gd202S：Eu3＋（8%） oxysulfide sample synthesized using crystalline Gd（CO3）OH precursor, than for that obtained from amorphous Gd2（OH）2（CO3）2.H20 precursor, although some further efforts to improve morphology of the former are still required.展开更多
基金Project supported by Polish Ministry of Science and Higher Education (N507 076 32/2186, RO 02 015 02 and N507 421236)
文摘The nanopowders of SnO2 doped with different Eu^3＋ concentrations were synthesized using the modified Pechini method. The Eu^3＋ concentrations were high above solubility limit. The average size of crystallites was controlled by the sintering temperatures. The structure and the morphology of obtained powders were examined using the XRD （X-ray diffraction） and TEM （transmission electron microscopy） analyses. The Eu2Sn2O7 phase separation was observed at relatively high concentration of Eu^3＋ ions. The ZnS：Ag micropowders were mixed with the Eu^3＋：SnO2 powders and their normalized emission was used to measure a relative efficiency of Eu3＋：SnO〉 The photoluminescence spectra of mixed powders were measured in function of Eu^3＋ concentration and average size of nanocrystallites. The reference peak method was used for comparison of intensities of the samples and selection of optimal one. The influence of the average grain size and Eu^3＋ concentration on the phosphor＇s efficiency was discussed. The presented results confirmed the rightness of synthesis of the Eu^3＋：SnO2 in form of nanocrystalites with relatively high Eu^3＋ concentration.
基金Project supported by Wroclaw Research Centre EIT+within the project"The Application of Nanotechnology in Advanced Materials”-Nano Mat(POIG.01.01.02-02-002/08) co-financed by the European Regional Development Fund(Operational Programme Innovative Economy,1.1.2)
文摘Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^-3 mol/L in a water solution containing relatively high, three molar concentration of urea ensured the optimal conditions for the reproducible preparation of uniform and small spherical particles. During sulfuration step elemental sulfur was mixed with precursor which eliminated necessity of using an auxiliary furnace and provided sulfur-reach reaction atmosphere. Such optimized protocol afforded synthesis of spherical and non-agglomerated nanoparticles with diameter smaller than 100 nm. The precursors morphology was maintained, but particles size was reduced by 15%-20% during sulfuration. The results indicated that higher emission intensity was observed for Gd202S：Eu3＋（8%） oxysulfide sample synthesized using crystalline Gd（CO3）OH precursor, than for that obtained from amorphous Gd2（OH）2（CO3）2.H20 precursor, although some further efforts to improve morphology of the former are still required.
