Rational control of photoluminescence against a change in temperature is important for fundamental research and technological applications. Herein, we report an anomalous temperature dependence of upconversion luminescence in Yb/Ho co-doped Sc₂Mo₃O₁₂ crystals. By leveraging negative thermal expansion of the crystal lattice, energy transfer between the lanthanide dopants is promoted as the temperature is increased from 303 to 573 K, resulting in an ∼5-fold enhancement of the emission. Meanwhile, the emission profile is also substantially altered due to the concurrent thermal quenching of selective energy states, corresponding to a clear shift in color from green to red. Via correlation of the red-to-green emission intensity ratio of Ho³⁺ dopant ions with temperature, a ratiometric luminescence thermometer is constructed with a maximum sensitivity of 2.75% K^–1 at 543 K. As the Sc₂Mo₃O₁₂ crystals are thermally stable and nonhygroscopic, our findings highlight a general approach for highly reversible control of upconversion by temperature in ambient air.

中文翻译：

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Sc ₂ Mo ₃ O ₁₂晶体中通过热刺激同时增强和上转换的调制

合理控制光致发光以防止温度变化对于基础研究和技术应用很重要。在此，我们报道了Yb / Ho共掺杂Sc ₂ Mo ₃ O ₁₂晶体中上转换发光的温度异常关系。通过利用晶格的负热膨胀，随着温度从303 K升高到573 K，镧系元素掺杂剂之间的能量转移得以促进，从而使发射强度提高了约5倍。同时，由于同时发生的选择性能量状态的热猝灭，发射轮廓也大大改变，这对应于颜色从绿色到红色的明显变化。通过Ho ^3+的红绿发射强度比的相关性随温度变化的掺杂离子，构建了比例发光温度计，在543 K时的最大灵敏度为2.75％K ^–1。由于Sc ₂ Mo ₃ O ₁₂晶体是热稳定且不吸湿的，因此我们的发现凸显了高度可逆控制的通用方法在环境空气中因温度而发生的上转换。