Synthesis and photoluminescence investigation of (Ba0.97-xMx)Y2Si3O10:0.03Eu2+ and Ba0.97(Y2-yREy)Si3O10:0.03Eu2+ (M = Ca, Sr; RE = La, Yb) by cation substitution

Abstract

By substituting Ca2+ or Sr2+ for Ba2+ and Yb3+ or La3+ for Y3+, in whole or in part, the single-phased Ba0.97-xMxY2Si3O10:0.03Eu2+ and Ba0.97Y2-yREySi3O10:0.03Eu2+ phosphors (M=Sr2+ or Ca2+, RE=La3+ or Yb3+) were synthesized successfully via high temperature solid-state reaction method. The introduction of different cations caused higher covalence and rigidity of the as-prepared samples and enhanced the interaction between electrons around Eu2+ ions, leading to the variation of emission color from bluish violet to light blue or greenish blue upon optimum excitation wavelength. In addition, the effect of cation substituting level on thermal stability of BaY2Si3O10:0.03Eu2+ was investigated in details. The emission intensities of Ba0.97-xY2Si3O10:0.03Eu2+, xSr2+, Ba0.97-xY2Si3O10:0.03Eu2+, xCa2+, Ba0.97Y2-ySi3O10:0.03Eu2+, yYb3+ and Ba0.97Y2-ySi3O10:0.03Eu2+, yLa3+ varied in the range of 68.09%–78.64%, 78.44%–81.00%, 67.38%–79.90% and 60.25%–79.84% at 423K compared to the initial intensity at room temperature, respectively. Meanwhile, the crystal filed split effect (CFSE) and nephelauxetic effect (NE) mechanisms were also proposed to better explain the red shifts and the changes of thermal quenching behavior of above samples. This work shed some light on the design of phosphors with controllable emission colors and higher thermal stability for the applications in phosphor-converted devices.