Bright upconversion emission and large strain in Er/Sb-codoped (Bi0.5Na0.5)0.945Ba0.065TiO3 ceramics

Multifunctional ferroelectric ceramics (Bi0.5Na0.5)0.945Ba0.065Ti1−x(Er0.5Sb0.5)xO3 (BNBT6.5-100xES) with bright upconversion emission and field-induced large strain were prepared through conventional solid state sintering method. Results showed that Er/Sb-codoping into BNBT6.5 induced a phase transition from ferroelectric to ergodic relaxor phase. Near the phase boundary (x = 0.50%), a large fatigue-resistant strain of 0.40% at a driving field of 80 kV/cm was obtained. Besides the excellent strain properties, Er/Sb-codoped BNBT6.5 samples exhibited a strong photoluminescence with a bright green emission at 526 nm and 549 nm assigned to (2H11/2, 4S3/2) → 4I15/2 transitions and a relatively weak red emission located at 663 nm assigned to 4F9/2 → 4I15/2 transition under the 980 nm excitation. As a multifunctional material, it has potential application as a multifunctional device such as “on-off” actuator, optical-electro integration and coupling device applications.