Controllable Eu2+-Doped Orthophosphate Blue-/Red-Emitting Phosphors: Charge Compensation and Lattice-Strain Control

Cation-substitution-induced controllable luminescence tuning could efficiently optimize and improve the luminescence performances of novel phosphor materials for realizing high-quality lighting. As important members of the orthophosphate family, ABPO4 (A = alkali metal Li, Na, K, Rb, Cs; B = alkali earth metal Mg, Ca, Sr, Ba) offers an abundant cation lattice environment for rare earth ions. Herein, we successfully prepared a broad-band red-emitting CsMgPO4:Eu2+ phosphor with an emission peak at 628 nm (fwhm = 118 nm). A series of cation-substitution strategies are designed to adjust and enhance its luminescence performances. The corresponding mechanisms are also investigated and proposed reasonably. A charge-compensation strategy of [Eu2+-Si4+] → [Cs+-P5+] could dramatically enhance the quenching concentration from 0.04 to 0.30, which is attributed to the decrease of Eu3+. Two cation-substitution strategies of larger Ba2+ (Sr2+) ions for Mg2+ ions could achieve superior emission adjustment of Eu2+ ions f...