Upconversion emission in Er-doped and Er/Yb-codoped ferroelectric Na0.5Bi0.5TiO3 and its temperature sensing application

Upconversion emissions of Er-doped and Er/Yb-codoped Na0.5Bi0.5TiO3 have been studied. Under 980 nm excitation, all samples exhibit strong green and red upconversion emissions, which can be seen by naked eyes. The Er/Yb-codoped Na0.5Bi0.5TiO3 ceramic has stronger upconversion emission intensity than Er-doped Na0.5Bi0.5TiO3 ceramic. Additionally, the optical temperature sensing properties based on upconversion emissions of Er/Yb-codoped Na0.5Bi0.5TiO3 ceramic were also investigated. The results demonstrate that the maximum sensitivity and temperature sensing resolution were 0.0031 K−1 and 0.3 K respectively, suggesting that the Er/Yb-codoped Na0.5Bi0.5TiO3 has potential application as optical temperature sensing materials.