Two-step synthesis of Y2O3:Eu nanostructures was performed.It includes microwave driven hydrothermal and calcination stages.Performed route results in crystallization of Y4O(OH)g(NO3):Eu crystals initially,then Y2O3:E...Two-step synthesis of Y2O3:Eu nanostructures was performed.It includes microwave driven hydrothermal and calcination stages.Performed route results in crystallization of Y4O(OH)g(NO3):Eu crystals initially,then Y2O3:Eu crystals after calcination.Arranged Eu contents in relation to overall cation quantity were set to 2 mol%,10 mol%and 20 mol%.Varying europium concentrations influence habit of obtained Y4O(OH)g(NO3):Eu crystals from needle-like to plate-like and as a result,also shapes of final Y2O3:Eu nanostructures.Additionally,certain amount of Eu2+ions was detected in as-grown material using laser spectroscopy and decay kinetics measurements.Obtained material was calcined at 1200°C in the air,which results in oxidation of Eu2+ions and crystallization of small number of cubic EU2 O3 nanocrystals.Characterization of obtained materials was performed using XRD,SEM,TEM,EDX,CL,Raman and photoluminescence spectroscopy.展开更多
Monodisperse silica/aminosilane-coated Y 2 O 3:Yb,Ho nanoparticles are prepared via homogenous precipitation combined with a polyvinylpyrrolidone-assisted ammoniation method.The factors that contribute to the success ...Monodisperse silica/aminosilane-coated Y 2 O 3:Yb,Ho nanoparticles are prepared via homogenous precipitation combined with a polyvinylpyrrolidone-assisted ammoniation method.The factors that contribute to the success of the coating are examined,and the procedure is optimized.Compared with uncoated nanoparticles,coated nanoparticles exhibit an increased ratio of green to red emission intensity,which can mainly be attributed to the decreased number of surface defects induced by the surface coating.展开更多
Terbium doped yttrium oxide was prepared with the microwave hydrothermal method. The Y2O3：Tb nanomaterial crystal- lized as needle-like grains. Bright luminescence in the green region was observed. Significant lumine...Terbium doped yttrium oxide was prepared with the microwave hydrothermal method. The Y2O3：Tb nanomaterial crystal- lized as needle-like grains. Bright luminescence in the green region was observed. Significant luminescence intensity increase was obtained after thermal treatment. Reduction of terbium ions was observed after heating in the air atmosphere. Tb4＋ ions were found to be stabilized by crystal impurities. Hydroxyl species were found to have impact on vacancies elimination. The terbium ions were used as optical and magnetic indicator of the material properties.展开更多
YAG powders with different Sm concentrations were synthesized by nitrate-citrate sol-gel combustion method. Phase evolution, morphology and luminescent properties of the obtained materials were characterized by XRD, F...YAG powders with different Sm concentrations were synthesized by nitrate-citrate sol-gel combustion method. Phase evolution, morphology and luminescent properties of the obtained materials were characterized by XRD, FESEM, photoluminescent excited by purple light, respectively. Powder X-ray diffraction showed that cubic YAG∶Sm crystallites were directly obtained at 800 ℃ from amorphous materials. The crystallization stage was characterized by an exothermic peak of DSC curve at 910 ℃. FESEM micrographs revealed that the resultant phosphors were agglomerated with an average particle size of about 300 nm. The photoluminescence spectra excited by 405 nm wavelength showed several obvious emission bands located in the 550～700 nm, corresponding to 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 transitions of Sm3+ ions, respectively. For luminescence property, the emission intensity of YAG∶Sm powders varied with the Sm contents and reached the maximum at 3%(mole fraction) Sm.展开更多
High transparency in visible region was required for red-light-emitting Y2O3:Eu3+ thin film phosphors. Such films were obtained via chemical bath deposition on bare SiO2 glass substrates through heterogeneous nucleati...High transparency in visible region was required for red-light-emitting Y2O3:Eu3+ thin film phosphors. Such films were obtained via chemical bath deposition on bare SiO2 glass substrates through heterogeneous nucleation with further heat treatment. Thin amorphous yttrium basic carbonate films could be completely transformed to crystalline Y2O3 at 650 °C. X-ray diffraction and field-emission scanning electron microscopy were used to characterize these products. The deposition temperature and the post-anneali...展开更多
基金Project supported by National Science Centre(2012/05/E/NZ4/02994,2012/06/A/ST7/00398)
文摘Two-step synthesis of Y2O3:Eu nanostructures was performed.It includes microwave driven hydrothermal and calcination stages.Performed route results in crystallization of Y4O(OH)g(NO3):Eu crystals initially,then Y2O3:Eu crystals after calcination.Arranged Eu contents in relation to overall cation quantity were set to 2 mol%,10 mol%and 20 mol%.Varying europium concentrations influence habit of obtained Y4O(OH)g(NO3):Eu crystals from needle-like to plate-like and as a result,also shapes of final Y2O3:Eu nanostructures.Additionally,certain amount of Eu2+ions was detected in as-grown material using laser spectroscopy and decay kinetics measurements.Obtained material was calcined at 1200°C in the air,which results in oxidation of Eu2+ions and crystallization of small number of cubic EU2 O3 nanocrystals.Characterization of obtained materials was performed using XRD,SEM,TEM,EDX,CL,Raman and photoluminescence spectroscopy.
基金supported by the National Natural Science Foundation of China(60979003)the Program for New Century Excellent Talents Plan of the Ministry of Education of China(NCET-10-0171)the Scientific Research Fund of Liaoning Province Education Department(2009A095)
文摘Monodisperse silica/aminosilane-coated Y 2 O 3:Yb,Ho nanoparticles are prepared via homogenous precipitation combined with a polyvinylpyrrolidone-assisted ammoniation method.The factors that contribute to the success of the coating are examined,and the procedure is optimized.Compared with uncoated nanoparticles,coated nanoparticles exhibit an increased ratio of green to red emission intensity,which can mainly be attributed to the decreased number of surface defects induced by the surface coating.
基金Project supported by European Union within European Regional Development Fund,through Grant Innovative Economy(POIG.01.01.02-00-008/08)
文摘Terbium doped yttrium oxide was prepared with the microwave hydrothermal method. The Y2O3：Tb nanomaterial crystal- lized as needle-like grains. Bright luminescence in the green region was observed. Significant luminescence intensity increase was obtained after thermal treatment. Reduction of terbium ions was observed after heating in the air atmosphere. Tb4＋ ions were found to be stabilized by crystal impurities. Hydroxyl species were found to have impact on vacancies elimination. The terbium ions were used as optical and magnetic indicator of the material properties.
基金the National Defence Fundamental Research Project of China and Jiangsu Province Natural SciencesFund (BK2007724)
文摘YAG powders with different Sm concentrations were synthesized by nitrate-citrate sol-gel combustion method. Phase evolution, morphology and luminescent properties of the obtained materials were characterized by XRD, FESEM, photoluminescent excited by purple light, respectively. Powder X-ray diffraction showed that cubic YAG∶Sm crystallites were directly obtained at 800 ℃ from amorphous materials. The crystallization stage was characterized by an exothermic peak of DSC curve at 910 ℃. FESEM micrographs revealed that the resultant phosphors were agglomerated with an average particle size of about 300 nm. The photoluminescence spectra excited by 405 nm wavelength showed several obvious emission bands located in the 550～700 nm, corresponding to 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 transitions of Sm3+ ions, respectively. For luminescence property, the emission intensity of YAG∶Sm powders varied with the Sm contents and reached the maximum at 3%(mole fraction) Sm.
基金Project supported by the National Basic Research Program of China (2007CB936704)Major Basic Research Program of Shanghai (07DJ14001)+2 种基金"Pujiang Talent Project" of Shanghai Science and Technology Committee (09PJ1410600)Innovation Group for the Ministry of Science and Technology of ChinaPHD Innovation Program 2009 by NSRL of Ministry of Education
文摘High transparency in visible region was required for red-light-emitting Y2O3:Eu3+ thin film phosphors. Such films were obtained via chemical bath deposition on bare SiO2 glass substrates through heterogeneous nucleation with further heat treatment. Thin amorphous yttrium basic carbonate films could be completely transformed to crystalline Y2O3 at 650 °C. X-ray diffraction and field-emission scanning electron microscopy were used to characterize these products. The deposition temperature and the post-anneali...
