High Dielectric, Piezoelectric, Upconversion Photoluminescence and Low-Temperature Sensing Properties in Ba0.7Sr0.3TiO3-BaZr0.2Ti0.8O3:Ho/Yb Ceramics

In the present work, we have synthesized pure and Ho/Yb-co-doped 0.5Ba(0.7)Sr(0.3)TiO(3)-0.5BaZr(0.2)Ti(0.8)O(3) ceramics using a solid-state reaction technique. The prepared pure 0.5Ba(0.7)Sr(0.3)TiO(3)-0.5BaZr(0.2)Ti(0.8)O(3) ceramics were found in the morphotropic phase boundary region, and exhibit high piezoelectric and dielectric properties. Under a 980-nm excitation, strong green, red and near-infrared (NIR) upconversion (UC) photoluminescence is observed in Ho/Yb-co-doped samples. It is found that the color of UC emission could be tuned by changing the concentration of sensitizer Yb ions in the host matrix. Furthermore, optical temperature sensing properties based on the green and NIR UC emissions of BSZT:0.005Ho/0.01Yb were investigated. Fluorescence intensity ratio (FIR) between green (F-5(4),S-5(2)) -> I-5(8) and NIR (F-5(4),S-5(2)) -> I-5(7) UC emissions of Ho ions was studied as a function of temperature in the range of 78 K-373 K, and a maximum sensitivity 0.0206 K-1 at 97 K was obtained.