Effects of temperature and electric field on upconversion luminescence in Er 3+ ‐Yb 3+ codoped Ba 0.8 Sr 0.2 TiO 3 ferroelectric ceramics

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 1.07×10 −2 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.