Zou Hua, Chen Bing, Hu Yifeng, Zhang Qiwei, Wang Xusheng, Wang Feng
School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China.
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
J Phys Chem Lett. 2020 Apr 16;11(8):3020-3024. doi: 10.1021/acs.jpclett.0c00628. Epub 2020 Apr 3.
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 ScMoO 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 Ho dopant ions with temperature, a ratiometric luminescence thermometer is constructed with a maximum sensitivity of 2.75% K at 543 K. As the ScMoO crystals are thermally stable and nonhygroscopic, our findings highlight a general approach for highly reversible control of upconversion by temperature in ambient air.
对于基础研究和技术应用而言，针对温度变化对光致发光进行合理控制至关重要。在此，我们报道了Yb/Ho共掺杂的ScMoO晶体中反常的上转换发光温度依赖性。通过利用晶格的负热膨胀，当温度从303 K升高到573 K时，镧系掺杂剂之间的能量转移得到促进，导致发射增强约5倍。同时，由于选择性能级的同时热猝灭，发射光谱也发生了显著变化，对应着颜色从绿色到红色的明显转变。通过将Ho掺杂离子的红/绿发射强度比与温度相关联，构建了一种比率发光温度计，在543 K时的最大灵敏度为2.75% K。由于ScMoO晶体具有热稳定性且不吸湿，我们的研究结果突出了一种在环境空气中通过温度对上转换进行高度可逆控制的通用方法。
