Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scann...Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.展开更多
Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980...Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980 nm laser excitation. The results of XRD showed that the obtained Y2O3：Er^3＋,Yb^3＋ nanoparticles were of a cubic structure. The average crystallite sizes calculated were in the range of 28-40 nm. Green and red upconversion emission were observed, and attributed to ^2H11/2,^4S3/2→^4I15/2 and ^4F9/2→^4I15/2 transitions of the ion, respectively. The ratio of the intensity of green emission to that of red emission drastically changed with a change in the EDTA 2Na concentration. In the sample synthesized without EDTA, the relative intensity of the green emission was weaker than that of the red emission. The relative intensities of green emission increased with the increased amount of EDTA 2Na used. The possible upconversion luminescence mechanisms were discussed.展开更多
The three composites Y2O3 :Er3+ , Y2O3 :Er3+ /Yb 3+ andY2O3 :Er3+ /TiO2 were prepared using coprecipitation and sol-gel techniques. Their morphology, specific surface area, porosity, UV-vis. absorption spectra and flu...The three composites Y2O3 :Er3+ , Y2O3 :Er3+ /Yb 3+ andY2O3 :Er3+ /TiO2 were prepared using coprecipitation and sol-gel techniques. Their morphology, specific surface area, porosity, UV-vis. absorption spectra and fluorescence spectra were measured using SEM, TEM, surface analysis, UV-vis. absorption and photoluminescence spectrophotometry. SEM and TEM showed that samples prepared using coprecipitation were dispersed, while Y2O3 :Er3+ /TiO2 particles possessed a mesoporous surface and average diameter of about 10 nm. The specific surface area and porosity of Y2O3 :Er3+ /TiO2 did not result from the combination of the individual properties of Y2O3 :Er3+ and TiO2 . The specific surface area of Y2O3 :Er3+ /TiO2 was 135.991 m 2 /g and was 4.8 times that of Y2O3 :Er3+ and 2.5 times that of Degussa P25 TiO2 . A high specific surface area is conducive for application to TiO2 photocatalysis. The fluorescence spectra of the three composites exhibited three upconversion emission peaks with maxima at 237, 395 and 467 nm following excitation at 388, 500 and 570 nm, respectively.展开更多
Er^（3＋） doped Y_2Ti_2O_7 phosphors were prepared by the high temperature solid state reaction method at 1500℃.X-ray diffraction and luminescence spectra were used to characterize the properties of samples.Due to t...Er^（3＋） doped Y_2Ti_2O_7 phosphors were prepared by the high temperature solid state reaction method at 1500℃.X-ray diffraction and luminescence spectra were used to characterize the properties of samples.Due to the layer distribution of Y^（3＋） ions in the pyrochlore Y_2Ti_2O_7 crystal,Er^（3＋） ions,replacing Y^（3＋） in Y_2Ti_2O_7 crystal,could realize high-concentration doping by suppressing energy migration between layers to minimize concentration quenching.Investigation on the upconversion characteristic of Y_2Ti_2O_7：Er^（3＋）showed that the optimal doping concentration of Er^（3＋） was up to 28 mol.%.Y_2Ti_2O_7：0.28 Er^（3＋） exhibited both dominating red emission under 980 and 1550 nm excitation.The brightness of Y_2Ti_2O_7：0.28Er^（3＋） were 4 times（980 nm） and 7 times（1550 nm） higher than that of Y_2Ti_2O_7：0.05Er^（3＋）.And Y_2Ti_2O_7：Er^（3＋） presented much better red emission color purity and stability under 1550 nm excitation.展开更多
基金supported by the grants from the Nature Science Foundation of Zhejiang Province (Y406309)Research Program from Science and Technology Bureau of Jinhua City (2008-1-151)
文摘Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.
基金the Foundation for the University by Educational Department of Liaoning (05L337)Key Laboratory of Rare Earth Chemistry and Physics, Chinese Academy of Sciences
文摘Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980 nm laser excitation. The results of XRD showed that the obtained Y2O3：Er^3＋,Yb^3＋ nanoparticles were of a cubic structure. The average crystallite sizes calculated were in the range of 28-40 nm. Green and red upconversion emission were observed, and attributed to ^2H11/2,^4S3/2→^4I15/2 and ^4F9/2→^4I15/2 transitions of the ion, respectively. The ratio of the intensity of green emission to that of red emission drastically changed with a change in the EDTA 2Na concentration. In the sample synthesized without EDTA, the relative intensity of the green emission was weaker than that of the red emission. The relative intensities of green emission increased with the increased amount of EDTA 2Na used. The possible upconversion luminescence mechanisms were discussed.
基金supported by the National Natural Science Foundation of China (20876125)the Research Fund for the Doctoral Program of Higher Education of China (20096101110013)+1 种基金the Natural Science Foundation of Shanxi Province (2010JZ002)the Northwest University Graduate Cross-discipline Fund (09YJC27and09YJC24)
文摘The three composites Y2O3 :Er3+ , Y2O3 :Er3+ /Yb 3+ andY2O3 :Er3+ /TiO2 were prepared using coprecipitation and sol-gel techniques. Their morphology, specific surface area, porosity, UV-vis. absorption spectra and fluorescence spectra were measured using SEM, TEM, surface analysis, UV-vis. absorption and photoluminescence spectrophotometry. SEM and TEM showed that samples prepared using coprecipitation were dispersed, while Y2O3 :Er3+ /TiO2 particles possessed a mesoporous surface and average diameter of about 10 nm. The specific surface area and porosity of Y2O3 :Er3+ /TiO2 did not result from the combination of the individual properties of Y2O3 :Er3+ and TiO2 . The specific surface area of Y2O3 :Er3+ /TiO2 was 135.991 m 2 /g and was 4.8 times that of Y2O3 :Er3+ and 2.5 times that of Degussa P25 TiO2 . A high specific surface area is conducive for application to TiO2 photocatalysis. The fluorescence spectra of the three composites exhibited three upconversion emission peaks with maxima at 237, 395 and 467 nm following excitation at 388, 500 and 570 nm, respectively.
基金supported by Research Program of Application Foundation(Main subject)of Ministry of Transport of China(2015329225090)the National Natural Science Foundation of China(11504039,51502031)Fundamental Research Funds for the Central Universities(3132015150,3132015153,3132015139,3132016349)
文摘Er^（3＋） doped Y_2Ti_2O_7 phosphors were prepared by the high temperature solid state reaction method at 1500℃.X-ray diffraction and luminescence spectra were used to characterize the properties of samples.Due to the layer distribution of Y^（3＋） ions in the pyrochlore Y_2Ti_2O_7 crystal,Er^（3＋） ions,replacing Y^（3＋） in Y_2Ti_2O_7 crystal,could realize high-concentration doping by suppressing energy migration between layers to minimize concentration quenching.Investigation on the upconversion characteristic of Y_2Ti_2O_7：Er^（3＋）showed that the optimal doping concentration of Er^（3＋） was up to 28 mol.%.Y_2Ti_2O_7：0.28 Er^（3＋） exhibited both dominating red emission under 980 and 1550 nm excitation.The brightness of Y_2Ti_2O_7：0.28Er^（3＋） were 4 times（980 nm） and 7 times（1550 nm） higher than that of Y_2Ti_2O_7：0.05Er^（3＋）.And Y_2Ti_2O_7：Er^（3＋） presented much better red emission color purity and stability under 1550 nm excitation.
