Preparation And Properties Of Several Red Long Afterlow Phosphorescent Materials

Recently,long lasting phosphor has been rapidly developed.The phosphors available include blue,green,and red etc.Till now,green and blue long-lasting phosphors have much better afterglow performance than red ones.The afterglow time of green phosphor and blue phosphor is longer than 10 h,while that of most red phosphors is not more than 5 h.But from the viewpoint of practical applications,it is urgent for the development of the phosphors with the emitting wavelength located at the longer side(red or orange)New red phosphors Sr2ZnSi2O7:Eu3+0,02,Lu3+0.02 were prepared by sot-gel method.And this phosphor can be clearly seen with naked eyes in a dark room over 18s after the irradiation source has been removed.The The properties and phosphorescent mechanism were also studied detailedly with various analytical measures.The properties of the samples were investigated systematically.Sr2ZnSi2O7:Eu3+,Lu3+phosphor has one emission peaks,and they are due to Eu3+ luminescent centers in the host.It was found the afterglow performance for the Sr2ZnSi2O7:Eu3+0.02,Lu3+0.02(Eu3+:Lu3+=1:1)phosphor was best.It was also found that the long afterglow performance of Sr2ZnSi2O7:Eu+ such as brightness and persistent time was largely improved when co-doped with Lu3+.The main reasons are ascribed to the more suitable depth of Lu3+ traps.The mechanism of the long afterglow was also discussed in this paper.Another part of this present dissertation was exploring research work on CaAl2O4-based long afterglow photoluminescent materials.Mn2+activated CaAl2O4 phosphors with long persistence were synthesized by the combustion method at lower temperature.The influence of the temperature of furnace,the content of the activator,the assistant activator,the flux and the combustibles etc were researched.The results indicated that the best temperature in the furnace for its synthesis was 600?,and the optimum sinter-ing temperature is 950?,and the optimum content of Eu2+and H3BO3 are 0.006 and 0.49 re-spectively.This phosphor can be clearly seen with naked eyes in a dark room over 1h after the irradiation source has been removed.Therefore,this phosphor will be a promising new kind of luminescent material for further investigation.Red Long lasting phosphorescent materials Zn3(PO4)2:Mn2+and Zn2.96(P1-0.8xSixO4)2:Mn2+0.04,were prepared by high temperature solid-state method,respectively.The XRD results show-ed that the addition of Si has no notable effects on the formation of Zn3(PO4)2 crystal structure.The excitationl and emission spectra of series doped materials were studied.The materia Is show red long lasting phosphorescence and the highest emission peak is located at 619.97 nm.The influence of the temperature of furnace,the content of Mn2+?Si4+ were researched.Afterglow time of simple produced under the best synthetic technology condition can last over 100 minutes.We also use different testing and analyzing methods to research the properties and afterglow mechanism.