Preparation And Luminescence Properties Of Rare Earth Ion Activatedsilicate Phosphors

In this paper, a series of K2 Zn Si O4:Eu3+, K2 Zn Si O4:Tb3+, Na2 Mg Si O4:Eu3+, Na2 Mg Si O4:Tb3+ phosphors were synthesized by solid state reaction, in which K2 Zn Si O4 and Na2 Mg Si O4 played the roles as hosts. The luminescent properties of the materials were analyzed with the emission spectrum, excitation spectrum, the color coordinates and other methods. The results were given as follows:(1) The red phosphor of K2 Zn Si O4:Eu3+ was prepared. The excitation spectra of the sample consist of charge transitions and Eu3+ ion excitation peak(350~500 nm). The maximum peak appears at 396 nm and the second peak appears at 466 nm. The phosphor presents several emission peaks under 396 nm and 466 nm excitation, which correspond to the 5D0â†'7FJ(J=0,1,2,3,4)transition of Eu3+, respectively, and the strongest emission is located at 619 nm. The luminescent intensity increases with increasing Eu3+ content. The concentration quenching does not occur.(2) The green fluorescent material of K2 Zn Si O4:Tb3+ was prepared. The excitation spectra of the sample consist of the strong 4f75d1 broad band absorption(200~300 nm) and the week 4fâ†' 4f electronic transition absorption(300~500 nm), corresponding to the characteristic excitation of Tb3+. The main excitation is located at 265 nm. The main emission is located at 545 nm under the excitation of 265 nm. The luminescent intensity increases with increasing Tb3+ content. The concentration quenching does not occur.(3) The red phosphor of Na2 Mg Si O4:Eu3+ was prepared. The excitation spectra of the sample consist of charge transitions(200~350 nm) and Eu3+ ion excitation peak(350~500 nm). The maximum peak appears at 396 nm. The maximum emission is located at 626 nm and the second is 598 nm under the excitation of 396 nm. The concentration quenching occurred with increasing Eu3+ content. The optimal doping concentration was 15%. The mechanism of concentration quenching is electric dipole-dipole interaction.(4) The green fluorescent material of Na2 Mg Si O4:Tb3+ was prepared. The maximum peak of excitation spectra appears at 376 nm and the others are 249 nm, 287 nm and 486 nm. The emission spectrum composed of four emission peaks which were 495 nm, 549 nm, 597 nm and 627 nm and corresponded to the 5D4â†'7FJ(J = 6, 5, 4, 3) level transition ofTb3+. The strongest emission peak was 549 nm. The concentration quenching occurred with increasing Tb3+ content. The optimal doping concentration was 15%. The mechanism of concentration quenching is electric dipole-dipole interaction.