Weijia Ding

Luminescence Properties of Sm3+ doped Bi2ZnB2O7

Abstract The phosphors of (Bi1-xSmx)2ZnB2O7(x = 0.01, 0.03, 0.05, 0.07, and 0.09) were synthesized by conventional solid state reaction. The purity of all samples was checked by X-ray powder diffraction (XRD). XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7, indicating that the Bi3+ in Bi2ZnB2O7 can be partly replaced by the Sm3+ without the change of crystal structure. The excitation and emission spectra at room temperature show the typical 4f-4f transitions of Sm3+. The dominant excitation line is around 404 nm due to 6H5/2→4K11/2 and the emission spectrum consists of a series of lines at 563, 599, 646, and 704 nm due to 4G5/2→6H5/2, 6H7/2, 6H9/2, and 6H11/2, respectively. The optimal concentration of Sm3+ in Bi2ZnB2O7 is about 3mol% (relative to 1mol Bi3+) and the critical distance Rc was calculated as 2.1 nm. The temperature dependence of the emission intensity of Bi1.94Sm0.06ZnB2O7 was examined in the temperature range between 100 and 450 K. The quenching temperature where the intensity has dropped to half of the initial intensity is 280 K. The lifetime for Sm3+ in Bi1.94Sm0.06ZnB2O7 is fitted as a value of 0.29 and 1.03 ms.

Luminescence Properties of Ca 1x Sr x "Ga 1y Al y … 2 S 4 :Eu 2+ and Their Potential Application for White LEDs

A series of Ca1�xSrxGa1�yAly2S4:0.10Eu 2+ 0.0 x 1.0, y = 1.0; 0.0 y 1.0, x =0 phosphors was synthesized by the evacuated sealed quartz ampoule method. X-ray powder diffraction analysis confirmed the formation of the complete solid solutions of Ca1�xSrxAl2S4:0.10Eu 2+ and CaGa1�yAly2S4:0.10Eu