Cao Jiafeng, Zhang Jia, Li Xiaowei
Appl Opt. 2018 Feb 20;57(6):1345-1350. doi: 10.1364/AO.57.001345.
To explore new upconversion (UC) luminescent materials for optical temperature sensing, a series of BaLa(PO):0.1Yb,xEr (abbreviated as BLP:0.1Yb, xEr, 0.01≤x≤0.03) and BaLa(PO):0.1Yb,yTm (abbreviated as BLP:0.1Yb, yTm, 0.005≤y≤0.015) phosphors was designed. For Yb-Er codoped BLP, the UC emission spectra exhibit a gradual enhancement with increasing pump power, and two-photon process for the green and red emissions of Er has been confirmed by studying the dependence of UC emission intensities on excitation power. When the temperature rises, the fluorescence intensity ratio (FIR) for the H2-I and S4-I emissions of Er increases gradually due to the thermalization of populations at the H2 and S4 levels. With the temperature increased, the absolute sensitivity (S) shows a continuous increase and reaches about 4.38×10 K at 498 K, but the relative sensitivity (S) decreases gradually. For Yb-Tm codoped BLP, the emission intensity of Tm shows a gradual decrease with increasing Tm concentration. By studying the temperature dependence of FIR for the (F3,F3)-H3 and H3-H emissions, it has been found the sample exhibits a higher S value but a lower S value relative to the Yb-Er codoped BLP.
为了探索用于光学温度传感的新型上转换（UC）发光材料，设计了一系列BaLa(PO₄)₃:0.1Yb,xEr（简称为BLP:0.1Yb,xEr，0.01≤x≤0.03）和BaLa(PO₄)₃:0.1Yb,yTm（简称为BLP:0.1Yb,yTm，0.005≤y≤0.015）荧光粉。对于Yb-Er共掺杂的BLP，上转换发射光谱随泵浦功率增加而逐渐增强，通过研究上转换发射强度对激发功率的依赖性，证实了Er的绿色和红色发射的双光子过程。当温度升高时，由于H₂和S₄能级上的粒子热化，Er的H₂-I和S₄-I发射的荧光强度比（FIR）逐渐增加。随着温度升高，绝对灵敏度（S）持续增加，在498 K时达到约4.38×10⁻⁴ K⁻¹，但相对灵敏度（Sr）逐渐降低。对于Yb-Tm共掺杂的BLP，Tm的发射强度随Tm浓度增加而逐渐降低。通过研究（F₃,F₃）-H₃和H₃-H发射的FIR的温度依赖性，发现该样品相对于Yb-Er共掺杂的BLP表现出较高的S值但较低的Sr值。
