Study On The Doping Of Rare Earth Ions And Application Of New Sodium-Zinc-Aluminum Phosphate Glass

White light-emitting diodes?W-LEDs?have gradually developed into the most ideal new solid-state lighting source due to the advantages of long service life,short response time,environment-friendly,and small size,etc.At present,the commercial W-LEDs are composed of blue InGaN chip with YAG:Ce³⁺yellow phosphor,and resin is used as phosphor packaging material,resulting in poor color rendering,high color temperature and poor thermal stability.In view of the above problems,a new type of Dy³⁺/Eu³⁺doped NZAP phosphor glass has been prepared by a special two-step method?solution combustion and low-temperature melt quenching method?.As to Dy³⁺/Eu³⁺doped NZAP phosphor glasses,Dy³⁺and Eu³⁺are luminescent ions while Na₂O-ZnO-Al₂O₃-P₂O₅?NZAP?glasses are used as matrix materials.The physicochemical properties and luminescent properties were studied,and realizing the preparation of NZAP phosphor glasses with excellent properties for W-LEDs.The structure and physicochemical properties of NZAP glass es were studied and indicated that:The structure of NZAP phosphor glasses are mainly composed of[PO₄]and[AlO₄]tetrahedral units,and forming a chain structure in the form of Q².For the 5Na₂O-35ZnO-5Al₂O₃-55P₂O₅ glass matrix,it has the best formability and thermal stability,and its average transmittance is up to 80%,its average thermal conductivity is 0.8 W/m K?which is four times as much as resin?.The results show that the glass matrix has excellent formability,thermal stability,optical transmission and thermal conductivity.The experimental results of NZAP:x%Dy³⁺and NZAP:y%Eu³⁺glassy phosphors prepared by low temperature combustion method show that the strongest excitation peaks of Dy³⁺and Eu³⁺ions are at 349 nm and 393 nm,and the strongest emission peaks are at 573 nm and 610 nm respectively.The optimum doping content of the two ions are 3 mol%and 2 mol%.Because crystals can not be precipitated in the matrix during the preparation process and no concentration quenching occurred under these concentrations,realizing good formability and high luminous intensity at the same time.The experimental results of Dy³⁺/Eu³⁺co-doped NZAP phosphor glasses prepared by a two step method show that the emitted light of Dy³⁺and Eu³⁺is generated simultaneously when excited by ultraviolet light at 349 nm.The energy transfer between Dy³⁺and Eu³⁺was confirmed by the overlapping of Dy³⁺emission spectra with Eu³⁺excitation spectra and fluorescence attenuation curves.Furthermore,it is analyzed that the energy transfer between Dy³⁺/Eu³⁺is dipole-dipole mechanism.The modification experiments of Dy³⁺/Eu³⁺co-doped NZAP phosphor glasses show that the glass prepared under reduction atmosphere of 20%H₂+80%N₂ can simultaneously produce Dy³⁺,Eu³⁺and Eu²⁺emission,and combine to obtain white light emitting.The NZAP:3%Dy³⁺,xEu³⁺glasses can achieve tunable warm white light emission under the excitation of 363 nm.Furthermore,the luminescence quantum efficiency of NZAP:3%Dy³⁺,0.5%Eu³⁺glass is up to 15%,the color coordinates and color temperature are?0.3592,0.3366?and 4361 K,respectively.Further analysis of its thermal quenching and aging properties show that the activation energy of thermal quenching is 0.19 eV,and the fluorescence intensity of the glass maintained 60.3%of its initial intensity after aging at 150?for 168 h.The NZAP:3%Dy³⁺,0.5%Eu³⁺glass were packaged into LED device with a 365 nm ultraviolet chip.The test results show that the color offset of the LED device under different current is only 4.43 x 10^-2,which can achieve excellent white light emission,indicating its good application prospects in the field of WLEDs.