Preparation And Properties Of Persistent Luminescent SrAl₂O₄:(Eu²⁺,Dy³⁺)

SrAl2O4:(Eu2+,Dy3+)is currently the best performance afterglow luminescent material in aluminate system,which has been widely used in the printing industry, paints, ceramics, textiles and other fields because of its better performance,such as high luminous intensity, long afterglow time, great chemical stability,no radiation and non-polluting. Nevertheless, SrAl2O4:(Eu2+, Dy3+) long-lasting materials still have many areas to improve and enhance. Although up to now, people has proposed several luminescent mechanism models on strontium aluminate, but these theoretical models can not fully explain the true principles of strontium aluminate luminescent materials. Therefore, it is necessary to get SrAl2O4:(Eu2+, Dy3+) light-emitting materials for more in-depth research.This paper described the development and application of SrAl2O4:(Eu2+, Dy3+) materials. The SrAl2O4:(Eu2+, Dy3+) light-emitting materials with a long afterglow effect were prepared by the high-temperature solid-phase method with carbon powder acted as reduction gas in the experiments. Using X-ray diffractometer(XRD), scanning electron microscopy(SEM), photoluminescent spectrometer(PL), UV-visible spectrophotometer(UV-Vis),we can analyze some materials’ characteristics, such as the crystal structure, surface topography, fluorescence spectroscopy and diffuse reflectance spectroscopy.The results show that: Under the high temperature of 1300℃ sintering europium and dysprosium co-doped strontium aluminate materials and hodling time 4h,we can get pure SrAl2O4 phase, and the temperature is too high or too low will result in the formation of impurity phase. And high temperature may cause the incorporation of rare earth elements exist in the form of crystals, that will decrease the light-emitting performance.Adding boric acid will promote mutual diffusion between materials, making it easier to grow up for strontium aluminate crystals, which can effectively shorten the process of solid-phase reaction. When the content of H3BO3 reach 5mol%, SrAl2O4:(Eu2+, Dy3+) luminescence properties will achieve the best.Through diffuse reflectance spectroscopy, we can find that Dy3+ doped will form a number of impurity levels in SrAl2O4 matrix, these levels are only as electronic storage, not involved in light emitting. Excess Eu2+ or Dy3+ ion doping, can lead to precipitation of Eu and Dy from matrix, that will make electrons on high energy levels annihilate in other forms.Testing the SrAl2O4:(Eu2+, Dy3+) persistent luminescent mixed with wear resistant epoxy resin, study found that the intensity of the mechanoluminescence produced was proportional to the exponential of the initial height of the ball(i.e., the final kinetic energy of the ball before impact) before falling down, and a decay curve was similar to that of persistent photoluminescence. The above results indicate that mechanoluminescence is caused by the impact energy of the ball which promotes electrons into traps, and then release via normal long persistent luminescent.