| During recent times, the studies on long-lasting afterglow materials havegiven rise to the attention of an increasing number of scholars because of theirgreat application potentials in several fields, for example, the emergencylighting, safety indicators, artificial fibers and biomedical nanodevices etc. Sofar, the colors of developed long-lasting phosphors include some monochromaticlight, such as red, green and blue. However, the white-light long-lastingmaterials are still under research due to the luminescent properties of thephosphors has yet to meet the requirements of practical application.In this work, white-light long-lasting micro-nanophosphors Y2O2S: Dy3+,Mg2+, Ti4+were synthesized via the hydrothermal method. And the effect ofvulcanizing temperature on the crystal characteristics, morphology andluminescent properties of the phosphors are discussed. On the basis of above, inorder to improve the luminous performance of the sample Y2O2S: Dy3+, Mg2+,Ti4+, we studied the influence of the concentrations of Dy3+, different divalentions, tetravalent ions and the doping amount of auxiliary active ions. Thedetailed research content were summarized: 1. First, the tube-like Y(OH)3: Dy3+, Mg2+, Ti4+precursor were synthesizedby the hydrothermal method. Then the phosphors Y2O2S: Dy3+, Mg2+, Ti4+wereobtained by calcinating the precursor in CS2atmosphere at750oC,800oC,850oC,900oC and950oC for6h, respectively. The samples were characterized bythe powder X-ray diffraction (XRD), scanning electron microscopy (SEM),photoluminescence (PL), chromaticity diagram (CIE), afterglow decay curvesand the thermoluminescence (TL) curves. The results showed that: the phase ofthe precursor is pure Y(OH)3, and present the tubular structure. The samplewhich were obtained at900oC present the pure Y2O2S phase andmicron-nano-sized particles. The chromaticity coordinates of the sample is (0.36,0.38). The initial intensity and the white afterglow emission of the sample were1604mcd/m2and2571s (≥1mcd/m2).2. In order to study the influence of the different concentrations of Dy3+ions on the Y2O2S: Dy3+, Mg2+, Ti4+white-light long-lasting phosphors, Y2O2S: xDy3+, Mg2+, Ti4+(x=0.5%,1.0%,1.5%,2.0%,2.5%) micro-nano particles wereprepared at the best curing temperature which obtained in experiment1. Theresults showed that: when the concentration of Dy3+was2.0%, the excitationand emission spectra of the sample were the strongest. The afterglow capabilitywas the best, and its optimal initial luminance was1925mcd/m2, the afterglowtime could last for over40min (≥1mcd/m2).3. In order to study the effect of the different divalent ions on Y2O2S: Dy3+,Mg2+, Ti4+luminescent materials, Y2O2S: Dy3+, M2+(M=Mg, Ca, Zn, Ba), Ti4+ samples were synthesis on the basis of the experiment1and2. The resultsshowed that the afterglow properties of samples doped with different divalentions decreased in accordance with the order Mg2+, Zn2+, Ca2+, Ba2+. When thedivalent ion was Mg2+, the sample showed the best afterglow performance.4. In order to study the effect of the different tetravalent ions on Y2O2S:Dy3+, Mg2+, Ti4+luminescent phosphors, Y2O2S: Dy3+, Mg2+, N4+(N=Ti, Si, Nb,Zr) powders were prepared based on the experiment1and2. The results showedthat the afterglow properties of samples doped with different divalent ionsdecreased in terms of the order Ti4+, Si4+, Nb4+, Zr4+. For the sample whichdoped with Ti4+, the afterglow performance of the sample was the best.5. For improving the luminescence properties of samples, we prepared theY2O2S: Dy3+, Mg2+, Ti4+phosphors by changing the doping amount of auxiliaryactivation ions (Mg2+, Ti4+) based on the experiments above. The results showedthat: when the content of (Mg2+, Ti4+) multiple-ion dopant was5.0%, theafterglow properties was the best. The optimal initial luminance of the samplewas2385mcd/m2and its afterglow time was4980s (≥1mcd/m2). |
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