Red emission of additional Pr³⁺ and adjusting effect of additional Mg²⁺ in Ca₃Sc₂Si₃O₁₂:Ce³⁺, Mn²⁺ phosphor

In this Letter, we report the addition of Pr3+ and Mg2+ in CSS:Ce3+, Mn2+ phosphor for improving the performances of white light-emitting diodes (LEDs). The additional trivalent Pr3+ will occupy the Ca2+ site in this host like the situation of Ce3+, its concentration can be enhanced by the addition of Mg2+ in Sc3+ site due to the substitution of Mg2+ for Sc3+ can compensate the charge mismatch between Pr3+ and Ca2+. Based on the efficient Ce3+→Pr3+ and Mn2+→Pr3+ energy transfers (ETs) and the compensation effect of Mg2+, the additional Pr3+ in our present phosphors exhibits an intense red-emission around 610 nm, which is significant for enhancing the color rendering property. In addition, we also find that the additional Mg2+ in Sc3+ site can markedly adjust the photoluminescence (PL) spectrum shape of our phosphor by controlling the distribution of Mn2+ at Ca2+ and Sc3+ sites. A new tunable full-color emission is obtained via the ETs (Ce3+→Mn2+, Ce3+→Pr3+ and Mn2+→Pr3+) and the adjusting effect of Mg2+ in our present phosphors. Finally, a white LED with higher color rendering index of 90, lower correlated color temperature of 4980 K, and chromaticity coordinates of (0.34, 0.31) was obtained by combining the single CSS:0.08Ce3+, 0.01Pr3+, 0.3Mn2+, 0.2Mg2+ phosphor with a blue-emitting InGaN LED chip.