Preparation And Luminescent Properties Of Rare Earth Ion Activated Ca₃Y₂（Si₃O₉）₂Phosphor

In this paper, Eu3+, Sm3+, Tb3+or Dy3+doped Ca3Y2(Si3O9)2phosphors were synthesizedby high temperature solid-state reaction, and their photoluminescent properties wereinvestigated. The research content and results as follows:(1) Ca3Y22x(Si3O9)2:2xEu3+are the orange-red phosphor. There are two excitation bands,namely, the O2–Eu3+intensive charge transition band (CTB) and the weak f f transitionabsorption of Eu3+in the excitation spectra. The main emissions are located at587nm(5D0â†'7F1) and610nm(5D0â†'7F2) under the excitation of225nm, and the intensity of theformer is similar to that of the latter. However, under the excitation of392nm, the intensiveemission is located at615nm and the weak emission is located at591nm. The effect of Eu3+content on the emission spectra intensity of Ca3Y2(Si3O9)2:Eu3+was investigated. Theluminescent intensity increases with increasing Eu3+content. The concentration quenchingdoes not occur.(2) The excitation spectra of orange-red phosphors Ca3Y22x(Si3O9)2:2xSm3+contain thecharacteristic excitation of Sm3+. The emission spectra of Ca3Y2(Si3O9)2:Sm3+phosphorsexhibit three main peaks, and the dominating emission peak is located at604nm(4G5/2â†'6H7/2). The luminescence intensity firstly increases with increasing of Sm3+content,and then decreases, the emission reaches the maximum intensity at x=0.02. The concentrationquenching mechanism is the electric dipole–electric dipole interaction.(3) The Ca3Y22x(Si3O9)2:2xTb3+phosphors excitation spectra are composed of the strong4f75d1broadband absorption (200-300nm) and the week4fâ†'4f electronic transitionabsorption (300-500nm), corresponding to the characteristic excitation of Tb3+. The mainexcitation is located at236nm. The main emission is located at544nm(5D4â†'7F5) under theexcitation of236nm,376nm or482nm. Respectively,236nm,376nm or482nm as theexcitation source, to monitor the decay time of the the emission peak, finds that the decaytime is the longest under the excitation of236nm and the decay time is the shortest under theexcitation of482nm. The effect of Tb3+content on the emission spectra intensity and the decay time were investigated. The results show that the decay time is decrease with raisingTb3+content, but the emission spectra intensity increases with raising Tb3+content, viz theconcentration quenching has not existed.(4) The Ca3Y22x(Si3O9)2:2xDy3+phosphors excitation spectra are composed of a seriesof narrow lines spectra peaks, corresponding to the characteristic excitation of Dy3+. Underthe excitation of347nm(6H15/2â†'6P7/2), the main emissions are located at482nm and573nm,corresponding to4F9/2â†'6H15/2and4F9/2â†'6H13/2transition, respectively. With increasing ofDy3+content, the luminescence intensity firstly increases, then decreases. And the maximumintensity of the emission peak is obtained at x=0.04. It is found that the concentrationquenching mechanism is the electric dipole–electric dipole interaction according to theDexter’s theory.