Papers by Keyword: Long Afterglow

Abstract: Road markings regulate and direct traffic by conveying specific information. It is of great significance to develop new road marking materials and improve the visibility of marking materials for improving traffic efficiency and ensuring traffic safety. This paper summarized the development status of various reflective road markings at home and abroad. In addition, the energy storage luminescent fluorescent/phosphor marking lines in road marking was emphatically generalized to evaluate the advantages and disadvantages of different improvement methods. Overall, strontium aluminate doped with Eu²⁺ co-doped with Dy³⁺ (SrAl₂O₄:Eu²⁺, Dy³⁺) phosphors and self-luminous pavement for energy storage had great prospects in improving road safety and reducing energy consumption.

Abstract: In this work, organic contaminants rhodamine B dyes in aqueous solution were decomposed by Ag₃PO₄ even without the lamp irradiation. This new photocatalytic system was established , in which Ag₃PO₄ could harvest persistent phosphorescence from SrAl₂O₄:(Eu,Dy). Such a self-luminescence-assisted process could enhance the performance of photocatalysts for environmental cleanup.

Abstract: In this paper, sol-gel method at low temperatures, an atmosphere of carbon reduction to replace the use of cyclodextrin system prepared with citric acid as SrAl₂O₄: Eu²⁺, Dy³⁺ Long Afterglow Phosphors nanotechnology. And the use of X-ray diffraction phase identification and fluorescence spectrophotometer with the excitation spectrum of the sample, luminescence spectra and luminescence afterglow to explore research, results show that product with the lower cost has the luminescence properties.

Abstract: ZnGa₂O₄ phosphors have been synthesized by solid state reaction at different temperatures with different B₂O₃ concentration incorporated in the experiments. All samples present green (509 nm) and red (696 nm) emission bands under ultraviolet excitation (250 nm), whose intensity changes because of the increasing B₂O₃ contents. The green and the red long afterglow have been observed after removing the ultraviolet light and the performance largely improves with the introduction of B₂O₃. The effects of the doping contents of B₂O₃ as well as the sintering temperatures on the luminescent properties of the obtained products have been investigated. The introduction of B₂O₃ changes the ratio of the two emitting centers and increases the depth of the trap centers in the samples.

Abstract: SrAl₂O₄:Eu²⁺, Dy³⁺ long afterglow phosphors were prepared by combustion synthesis and the influence of PEG dosages of the long afterglow phosphor on the luminescent properties was studied. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectroscopy (PL) and screen luminance meter. The main phase of the combustion products is SrAl²O⁴ with monoclinic crystal structure and the impurity phase content is reduced by adding PEG. Compared to the phosphor without PEG additive, the emission wavelength of the phosphor does not change, while the intensity of them is obviously enhanced. The optimum content of PEG was 0.4 mol% of the Sr²⁺, and the maximum initial brightness is 19110 mcd/m².

Abstract: The long afterglow phosphor CaAl₂O₄: Eu²⁺, Nd³⁺ was prepared by combustion synthesis, and the influence of glycine on the luminescent properties of the long afterglow phosphor was studied. The samples were characterized by X-ray diffraction (XRD) and fluorescence spectroscopy (PL) etc. The results showed that the main phase of the combustion products is CaAl₂O₄ with monoclinic crystal structure. The introduction of glycine prolongs the afterglow time.

Abstract: A new afterglow green phosphor of Zn₂SiO₄: Mn²⁺, Zr⁴⁺ was prepared by high temperature solid-state method. Effects of various preparation techniques on the crystal characteristics, luminescent properties and afterglow performance have been investigated systematically. The phosphor powders were further investigated by photoluminescence excitation and emission spectra (PL) and brightness meter. The results showed that the PL of Zn₂SiO₄: Mn²⁺, Zr⁴⁺ was observed in the green region due to transitions from the ⁴T_1g(G) to the ⁵A_1g(S) configuration of the Mn²⁺ ions. This phosphor showed obvious long-lasting phosphorescence that could be clearly seen with naked eyes in a dark room for more than 2h after the irradiation source has been removed. The possible mechanism of this phosphor was also investigated based on the TL measurements.

Abstract: Long afterglow phosphor is a special energy-saving material, which can store the energy of light irradiation and release light slowly. Ultrafine aluminate long afterglow phosphor is commonly prepared by the jet milling method. This method results in weak brightness, which restricts its application in delicate printing or textiles. In this study, fine particle aluminate phosphor (5μm) was coated by alumina, and then re-reduced under a high temperature. The alumina film works as a barrier layer, which protects the particles from sintering. The re-reduced phosphor had double afterglow brightness, and the size of the particle retained original level. The influences of pH value and KOH adding speed were investigated, the optimized parameters are: pH = 5, KOH adding speed = 2 ml/min.

Abstract: Long afterglow luminescent materials Sr_2-xCa_xMgSi₂O₇:Eu²⁺,Dy³⁺ （x=0-1.955）was synthesized by combustion method and characterized by X－ray diffraction,fluorescencespectrum and so on. Its preparing process conditions,the effect of Ca²⁺ replacing Sr²⁺ on its Luminescent performance were discussed. The results show it has a single phase and foamy structure,which is easy to be grinded into superfine powders. Its Luminescent property is importantly affected by water dosage(R= n_H2O /n_TEOS), reducer dosage (H=n_reducer /n_nitrate), gel grain dosage , gel grain size, arousing-burning temperature and burning time. Its best preparing process conditions are determined. A small quantity of Ca²⁺ replacing Sr²⁺ can raise its luminescence performance. Increasing Ca²⁺ content, its emission peak gradually wave to the long wave traverse, its luminous colors change from blue to yellow. Compared with the sample synthesized by high temperature solid reaction,the emission peaks of the sample synthesized by combustion method distinctly take place red shift.

Abstract: The M1.99MgSi2O7: Ce3+0.01 (M: Ba, Sr, Ca) phosphors were prepared by the solid-state reaction method. All the samples emit the violet-ultraviolet light with a broad emission band from about 330 nm to 500 nm. All the phosphors samples show a long afterglow. The strongest afterglow intensity and the longest decay duration of the afterglow come from the Ca1.99MgSi2O7: Ce3+0.01 sample. It is attributed to the suitable trap depth and the high trap concentration of this sample. The traps of these phosphors are induced by the lattice defects. A suitable model involving the cation vacancies and the oxygen vacancies, which act as the hole traps and the electron traps respectively, is proposed.