Mn 4+ -Activated Double-Perovskite-Type Sr 2 LuNbO 6 Multifunctional Phosphor for Optical Probing and Lighting.

Multifunctional phosphors have significant application and scientific value and are becoming a research hotspot in the field of luminescent materials. Herein, we report Mn ⁴⁺ -activated double-perovskite-type Sr ₂ LuNbO ₆ multifunctional phosphors with excellent comprehensive properties in the fields of optical temperature/pressure sensing and w-LED lighting. The crystalline structure, elemental composition, optimal doping concentration, crystal-field strength, and optical bandgap of the phosphors are investigated in detail, and the mechanisms of concentration and thermal quenching are discussed. From the optimal Sr ₂ LuNb _0.998 O ₆ :0.2%Mn ⁴⁺ phosphor, a LED lamp for indoor warm-white lighting is successfully fabricated. Further, the thermometric properties of the phosphors are explored for applications as FIR- and lifetime-based thermometers, showing a maximum relative sensitivity of 1.55% K ^-1 at 519 K. Upon pressure loading, a significant red-shift of the peak centroid is observed, and the pressure sensitivity is determined to be 0.82 nm/GPa. These results suggest that the Mn ⁴⁺ -activated Sr ₂ LuNbO ₆ multifunctional phosphors have great potential to be utilized in the fields of optical thermometry, manometry, and lighting.