For optical temperature sensing materials, the emission and excitation bands are extremely critical to measure the temperature by fluorescence intensity ratio (FIR) technique. Singly Ln‐doped optical temperature sensing materials exhibit very few emission bands, which greatly constraints their practical applications of FIR technique. Here, the fabricated Pr/Er co‐doped (K_0.5Na_0.5)NbO₃ materials exhibited multi‐color (red‐green) and dual‐mode (downshifting/upconversion) luminescence properties. The temperature sensitivity can be effectively tuned by choosing different emission or excitation bands. The optimized optical temperature sensitivity reached up to 0.0094 K⁻¹, much higher than that of most temperature sensing materials. Besides, the samples also showed excellent luminescence modulation properties based on the photochromic reaction. Under sunlight irradiation, the luminescent switching contrast (ΔR_t) of the samples reached more than 60%. These results may provide a guiding role in designing and modulating optical temperature sensing properties for multifunctional materials.

中文翻译：

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Pr / Er掺杂（K0.5Na0.5）NbO3材料中的光学温度感测和发光开关特性

对于光学温度感测材料，发射带和激发带对于通过荧光强度比（FIR）技术测量温度至关重要。仅掺Ln的光学温度感测材料几乎没有发射带，这极大地限制了FIR技术的实际应用。在此，预制的Pr / Er共掺杂（K _0.5 Na _0.5）NbO ₃材料表现出多色（红绿色）和双模（下移/上转换）发光特性。通过选择不同的发射或激发带可以有效地调节温度灵敏度。优化的光学温度灵敏度达到0.0094 K ^-1，比大多数温度感测材料要高得多。此外，基于光致变色反应，样品还显示出优异的发光调制特性。下太阳光的照射，发光开关对比度（Δ - [R_吨）样品的达到60％以上。这些结果可能为设计和调制多功能材料的光学温度感测特性提供指导作用。