Table 1 tabulated the CIE color coordinate and its simulated color, as well as the actual color under 390 nm illuminations. The color coordinate of Dy3+ singly doped SBS phosphor were (0.3426, 0.3892) for air sintered and (0.3463, 0.4208) for CO sintered, both phosphor emitted yellowish-white color under 390 irradiation. On the other hand, SBS phosphor doped with Eu2+/Eu3+ emit reddish-purple to blue color under irradiation of 390 nm UV light, the color was dependent on the sintering condition and Dy3+ co-doping. Samples doped with Eu3+/Eu2+ under air synthesis emits reddish-purple for its high Eu3+ content. While CO synthesized Eu3+/Eu2+ and Eu3+/Eu2+, Dy3+ co-doped ceramics showed bluish-purple emission. Lastly, Eu3+/Eu2+ and Dy3+ co-doped ceramics under CO synthesized emitted pure blue emission due to its high Eu2+ content. Therefore this study presented a possible reddish-purple to blue tunable phosphor by manipulating CO sintering atmosphere and Dy3+ co-doping. White phosphor were usually produced by RGB (red green blue) method (Liang et al. 2009). The presence of blue (Eu2+) and red (Eu3+) emission in the same host crystal offered itself as a promising candidate for white phosphor application.
FIGURE 5. Excitation spectrum of SrB2Si2O8:1 mol% Eu2+/Eu3+ and SrB2Si2O8:1 mol% Eu2+/Eu3+, 1 mol% Dy3+ synthesized under air and carbon monoxide atmosphere. λem = 435 nm (left), λem = 613 nm (right)