Papers by Keyword: Y2O2S

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Authors: Xiao Bao Han, Xiang Guo Li, Gui Hua Peng, Zhen Hua Liang, Xia Wang
Abstract: Nanocrystalline Y2O2S: Eu 3+ , Mg 2+ , Ti 4+ red long-lasting phosphor was synthesized successfully by combustion method using thiourea and citric acid as fuel. The structure, morphology and luminescent properties of these phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The experimental results revealed that the phosphor was composed of sheet-shaped Y2O2S with hexagonal crystal structure. They exhibited strong red emission at 617 nm and 626nm. In addition, the dosage of citric acid has great effect on the phosphor. When molar ratio of citric acid to Y 3+ is 1.3, the resulted phosphor gives the highest emission intensity.
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Authors: Peng De Han, Xiao Gu Huang, Qi Tu Zhang
Abstract: Up-conversion luminescent materials of Y2O2S: Yb, Tm with different doping concentrations of Tm3+ ion (0.5 mol%–4 mol %) and Yb3+ ion (4 mol%–16 mol %) were prepared by flux method. As Tm3+ doping concentration was 1 mol% and Yb3+ doping concentration was 8 mol%, the blue and red up-conversion luminescent intensity reached the maximum. The concentration quenching of Tm3+ was due to the reducing of the distance between Tm3+ ions and the cross-relaxation increasing. The concentration quenching of Yb3+ was attributed to increasing of nonradiative transition. The blue emission intensity of 1G43H6 was always weaker than the red emission intensity of 3F33H6, and the blue emission intensity of 1G43H6 is similar with the red emission intensity of 1G43F4.
558
Authors: Peng De Han, Le Zhang, Yan Chen, Li Xi Wang, Qi Tu Zhang
Abstract: Up-conversion luminescent materials of Y2O2S:Yb, Er with different doping concentrations of Er3+ ion (1 mol%–6 mol%) and Yb3+ ion (4 mol%–16 mol%) were prepared by flux method. As Yb3+ doping concentration was fixed at 8 mol%, when Er3+ doping concentration was 2 mol%, the green and red up-conversion luminescent intensity reached the maximum. As Er3+ doping concentration was fixed at 2 mol%, when Yb3+ doping concentration was 4 mol%, the green and red emission intensity reached the maximum. The up-conversion luminescent colours were adjustable.
381
Authors: Peng Yue Zhang, Zhang Lian Hong, Xian Ping Fan, Min Quan Wang
Abstract: Y1.97-xTi0.03CdxO2S (0≤x≤0.06) phosphors with long afterglow were synthesized by solid-state reaction. The photoluminescence spectra, decay curves, thermoluminescnece spectra and Chromaticity coordinate curves were investigated. Results showed that the luminescence and afterglow intensity of Y1.97-xTi0.03CdxO2S (0≤x≤0.06) reduced gradually with increasing Cd2+ ion content while the shape and position of emission peak remain unchanged. The Chromaticity coordinate of present phosphor keeps at (0.5497,0.4415). Furthermore, based on the results of thermoluminescence curves of Ti, Cd single doped and co-doped Y2O2S phosphors, the doped Cd ion reduces the inherent trap depth of Ti single doped Y2O2S:Ti, and induces simultaneously a new trap level in Y2O2S:Ti,Cd phosphor. Thus, it was proposed that the introduced new structure defect by Cd2+ ions should be responsible for the reducing luminescence and afterglow property.
604
Authors: Lu Lu, Zhi Long Wang
Abstract: The nano Y2O2S:Eu 3+0.01 were prepared with solvohtermal method. Using ethylenediamine as solvent, at 220°C for 12h , we get the best sample. The effect of various reaction times, surfactant in reaction on nano-particle size of the products were investigated in detail. Using the Laser granularity cryoscopy(rise 2008)to display the products size, the result shows that the sample size about 45nm, and the SEM shows that the morphology are nano wires. The emission spectrum shows that the strongest peak is located at 625nm, which attributed toEu 3+ ions’5D0-7 F2 transition.
129
Authors: Lu Lu, Zhi Long Wang, Ying Dong Li, Cheng Yi Li, Yi Li, Yi Zhou Du
Abstract: Series sample were prepared with solvothermal method using ethylene-diomine as solvent, at 220°C for 24h. All samples are white powder and XRD proofs that all of them are single phases. Using the Laser granularity cryoscopy (rise 2008) to measure the samples size , and most samples sizes are from 150nm to 200nm. SEM photo shows that the Y2O2S:Eu3+ morphologies are spherical but have some aggregation. And Y2O2S:Eu3+ has a better a anti-decay property compared with Rhodamine B. The Cell toxicity test (MTT) shows that when concentration range in 20-80mg/ml, the cytotoxicity of sample is relatively small ,but as a good bio-marker materials in tumors diagnosis , its toxicity is still high.
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