Multiple applications of Sr8ZnIn(1-m)Lum(PO4)7:Eu2+/Mn2+ through thermal stability adjustment, spectral tuning, and resonance energy transfer

The high-temperature solid-phase method was used in this research to construct a series of β-Ca₃(PO₄)₂-type Sr₈ZnIn_(1-m)Lu_m(PO₄)₇:xEu²⁺, yMn²⁺ (m = 0 – 1.0) phosphors. By varying the ratio of In/Lu, it was possible to achieve thermal stability and controlled tuning of the phosphor emission spectrum. The single-phase white phosphor Sr₈ZnIn_0.6Lu_0.4(PO₄)₇:0.02Eu²⁺, 0.05Mn²⁺ was produced by the doping of Mn²⁺, which encouraged the Eu²⁺ at various cation sites for rearrangement and produced customizable emission colors ranging from blue-green to orange-red. Finally, using its superior thermal stability, the FIR approach was used to construct an optical temperature sensor. The maximum relative sensitivity (S_r) and absolute sensitivity (S_a) of a typical sample reached 3.27 % K⁻¹ and 0.226 K⁻¹, respectively. At an operating current of 600 mA, the white light-emitting diodes based on Sr₈ZnIn_0.6Lu_0.4(PO₄)₇:0.02Eu²⁺, 0.05Mn²⁺ phosphors produced high-quality warm-white light with an excellent color rendering index (88.3) and an appropriate correlation color temperature (4522 K). Meanwhile, a series of snowflake patterns with temperature-dependent characteristics were prepared using it. From the dynamic color change, it can be seen that the material can retain information at different temperatures, thus realizing dynamic anti-counterfeiting. These findings demonstrate that a variety of uses for this phosphor series are possible.