No abstract

No abstract

Optical and electrical properties of 1%Er 3+ and different Yb 3+ content (1ExY) codoped Ba 0.8 Sr 0.2 TiO 3 (BST) ferroelectric ceramics fabricated by the solid-phase reaction were investigated. Under 980 nm pump condition, two green emission bands at 525 and 549 nm wavelength corresponding to, 2 H 11/2 ? 4 I 15/2 and 2 S 3/2 ? 4 I 15/2 transitions, and two red emission bands at 655 and 668 nm wavelength attributed to 4 F 9/2 ? 4 I 15/2 transition are observed. The temperature-sensing behaviors, calculated by the intensity ratio I 525 /I 549 suggested that, the maximum sensitivity of the green emission of the 1E8Y-BST ceramics is 1.07910 À2 K-1 at 293 K. Furthermore, the maximum sensitivity of 1E6Y-BST and 1E11Y-BST ceramics were obtained around the Curie temperature. The fluorescence lifetime of 1E8Y-BST ceramics for 2 H 11/2 level and 2 S 3/2 level shortened with the increase in the temperatures. Moreover, the upconversion (UC) luminescence intensity of 1E8Y-BST decreased with the increase in the external electric field and had a mutation at the coercive electric field (E c ) of about 1.24 kV/cm, which revealed that the electric field had influence on the UC luminescence. K E Y W O R D Sbarium titanate, Curie temperature, domains, ferroelectricity/ferroelectric materials