Synthesis?Characterization Of Triple Doped Phosphate Phosphors With Eu³⁺ And Other Metals Ions

White light-emitting LED is a new solid light emitting device.White light-emitting LED composed with red,green,blue three colours and excited with near UV light is a new white light LED technology solution.Red light-emitting phosphor used by the technology solution is most lacking,which it has not enough luminous intensity and other issues,so synthesis of the phosphor is current research focus.Therefore,to do correlative studies of the phosphor,improve its luminous intensity has an important significance to promote the development and progress of the new white light-emitting LED technology solution.After the literature research,this paper chose the above field to carry out the relevant experimental research work.First,active precursors were synthesized with low heating solid state reaction,then four novel kinds of phosphors([(La_0.8Y_0.2)PO₄]:Bi,Eu,Sm ?[(La_0.8Y_0.2)PO₄]: Al,Eu,Sm?[(La_0.8Y_0.2)PO₄]: Na,Eu,Sm and SrZn₂?PO₄?₂: Eu,Tb,Li)were obtained with calcination method under high temperature.The XRD,TG/DTG,SEM,UV-Vis,SEM and PLE&PL fluorescence spectra were used to characterize the precursors and the products of the above four kinds of phosphors.The main results and innovations of this paper are as follows:1.Four kinds of phosphors can be excited by the near-UV under about 392 nm and emit red light.They all have potential for using as red light emitting phosphor for white light LEDs excited by near-UV.2.For [(La_0.8Y_0.2)PO₄]: M,Eu,Sm?M = Bi,Al,Na?:?1?excitation peak of Eu³⁺ at 392 nm is enhanced and thicken by energy transfer from Sm³⁺ to Eu³⁺,and results to absorb near-UV light,thereby to increase the intensity of the emitting light of the phosphors;?2?There were only emission peak of Eu³⁺ in emission spectra,and emission peaks of Sm³⁺did not occur under excitation by near ultraviolet light at about 392 nm;?3?Three charge-compensating ions all have effect of sensitizing and enhancement for luminescence of Eu³⁺,the optimal doping concentrations of the ions are obtained;?4?Three kinds of phosphors all have emission spectra dominant by magnetic dipole?5D0?7F1?transition.?5?After comparison the fluorescence intensity of samples doped with charged compensation ion under optimal concentration and those of doped without charged compensation ion,it can be found that the formers are 2.66(Bi³⁺),1.64(Al³⁺)and 2.07?Na+?times of the latters.3.For SrZn₂?PO₄?₂:Eu,Tb,Li,Li+ and Tb³⁺ all have enhanced effect on luminescence of Eu³⁺.The optimal doping concentrations of the two ions were obtained,final influences on emission mode of Eu³⁺ by the co-doped ions were also known.In addition,the study also found that enhancement effect of Li+ on emission of Eu³⁺ had a ladder like enhancement effect,which the intensity of emission suddenly leapt to a step,then the variation in intensity liked a gentle straight line,no longer increased.Furthermore,there were only emission peaks of Eu³⁺ in emission spectra,and emission peaks of Tb³⁺ did not occur under excitation by near ultraviolet light at about 393 nm.The results indicated that energy has been transfered from Tb³⁺to Eu³⁺.After comparing the fluorescence intensity of the sample doped with charged compensation ion?Li+?under optimal concentration and those of undoped with charged compensation ion,it can be found that the former is 5.02 times of the latter.4.Sm³⁺ and Tb³⁺ can all transfer their energy to Eu3 + and enhance luminescence of Eu³⁺.But in contrast,because Sm³⁺ can enhance and widen excitation peak of Eu³⁺,so relatively speaking,the enhanced effect of doping Sm³⁺ is better than that of doping Tb³⁺.