YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated aver...YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated average crystallite sizes are in the range of 14-22 nm.The lattice constants and cell volume of the samples decrease slightly with the increase in Yb^3＋ concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green emission is observed,which is attributed to the 2^H11/2→4I15/2 and 4^S3/2→4^I15/2 transitions of Er^3＋,and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Yb^3＋concentration.These results reveal that the upconversion processes of YVO4：Er^3＋,Yb^3＋ are related to the structure and the doping Yb^3＋ concentration of the sample.展开更多
In this paper, we demonstrated trace of dye molecules in living plants. The NaGdF4:Yb^(3+),Er^(3+) nanoparticles probe was used to detect the rhodamine B(RhB) in bean sprout. It is found that the fluorescencedye can b...In this paper, we demonstrated trace of dye molecules in living plants. The NaGdF4:Yb^(3+),Er^(3+) nanoparticles probe was used to detect the rhodamine B(RhB) in bean sprout. It is found that the fluorescencedye can be efficiently imbibed during the growing process and the absorbance presented a position dependence effect, which was supported by the upconversion spectra and the fluorescent image characterization. In addition, the concentration of the residual RhB in bean sprout can be efficiently traced by the synthesized probe based on the fluorescent resonant energy transfer. Finally, the relation between the excitation power, concentration and the ratio of yellow to green emission are discussed in detail. These results can be helpful in understanding the RhB dye molecules absorbance process in vegetable growth and provide an efficient way to trace the residual dyes in vivo plant.展开更多
The KCI：Eu2＋ system response to UV-C was investigated by analyzing the optically stimulated luminescence （OSL） and ther- mo-luminescence （TL） signal produced by ultraviolet light exposure at room temperature. It...The KCI：Eu2＋ system response to UV-C was investigated by analyzing the optically stimulated luminescence （OSL） and ther- mo-luminescence （TL） signal produced by ultraviolet light exposure at room temperature. It was found that after UV-C irra.diation, OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2＋ aggregation state. In spite of the low intensity of solar UV-C reaching the Earth＇s surface in Madrid （40° N, 700 m a.s.1.）, it was possible to measure the UV-C radiation dose at 6：48 solar time by using the TL response of the KCI：Eu2＋ system and differentiate it from the ambient beta radiation dose.展开更多
基金supported by the Educational Department Project of Liaoning Province(No.2005319)
文摘YVO4：Er^3＋,Yb^3＋ with varying Yb^3＋ concentrations were prepared by a precipitation method.The results of X-ray diffraction （XRD） show that all the samples have a tetragonal zircon structure; the calculated average crystallite sizes are in the range of 14-22 nm.The lattice constants and cell volume of the samples decrease slightly with the increase in Yb^3＋ concentration.The upconversion luminescence spectra of all the samples were studied under 980 nm laser excitation.The strong green emission is observed,which is attributed to the 2^H11/2→4I15/2 and 4^S3/2→4^I15/2 transitions of Er^3＋,and the red emission peaks in 650-675 nm can be ignored.The emission intensity for the sample depends on the Yb^3＋concentration.These results reveal that the upconversion processes of YVO4：Er^3＋,Yb^3＋ are related to the structure and the doping Yb^3＋ concentration of the sample.
基金Project supported by the National Natural Science Foundation of China(61675067,51675174,61575062,61474042)the Scientific Research Fund of Hunan Provincial Education Department(16C0627,17B090)the Natural Science Foundation of Hunan Province,China(2016JJ2059,2018JJ3138)
文摘In this paper, we demonstrated trace of dye molecules in living plants. The NaGdF4:Yb^(3+),Er^(3+) nanoparticles probe was used to detect the rhodamine B(RhB) in bean sprout. It is found that the fluorescencedye can be efficiently imbibed during the growing process and the absorbance presented a position dependence effect, which was supported by the upconversion spectra and the fluorescent image characterization. In addition, the concentration of the residual RhB in bean sprout can be efficiently traced by the synthesized probe based on the fluorescent resonant energy transfer. Finally, the relation between the excitation power, concentration and the ratio of yellow to green emission are discussed in detail. These results can be helpful in understanding the RhB dye molecules absorbance process in vegetable growth and provide an efficient way to trace the residual dyes in vivo plant.
文摘The KCI：Eu2＋ system response to UV-C was investigated by analyzing the optically stimulated luminescence （OSL） and ther- mo-luminescence （TL） signal produced by ultraviolet light exposure at room temperature. It was found that after UV-C irra.diation, OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2＋ aggregation state. In spite of the low intensity of solar UV-C reaching the Earth＇s surface in Madrid （40° N, 700 m a.s.1.）, it was possible to measure the UV-C radiation dose at 6：48 solar time by using the TL response of the KCI：Eu2＋ system and differentiate it from the ambient beta radiation dose.
