Inorg. Chem. 2019, 58, 8, 5006–5012 https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.9b00028

Manipulating the distribution of rare earth activators in multiple cations’ sites of phosphor materials is an essential step to obtain tunable emission for the phosphor-converted white-light-emitting diodes (pc-WLEDs). However, it remains the challenge to realize the photoluminescence tuning in the single-phased phosphor with single activator, due to the uncertain location of doped ions and adjustable crystallographic sites. Herein we reported the β-Ca₃(PO₄)₂-type solid solution phosphors (Ca_8.98–xSr_x)MgK(PO₄)₇:2%Eu²⁺ (x = 0–8.98) and the effects of replacing Ca²⁺ by Sr²⁺ ions on the phase structures and color-tunable emission were investigated in detail. Tunable color emission has been realized by manipulating the redistribution of Eu²⁺ ions among different cation sites with adjustable chemical environment, and the related mechanism on the local structures has been discussed. The high R_a (85) and low color temperature (CCT) (4465 K) values of the as-fabricated WLEDs lamp indicate that (Ca_4.98Sr₄)MgK(PO₄)₇:2%Eu²⁺ can act as a promising white-emitting phosphor for single-phased pc-WLEDs. This work provides a new insight into the tuning of the compositions and multiple activator sites toward single-phased white emission.