Electro- and photon-induced cooling in BNT-BT-SBET relaxors with in situ optica temperature sensing

摘要

A novel lead-free luminescent ferroelectric (FE) ceramic, Bi0.5Na0.5TiO3-0.06 BaTiO3-0.055 Sr0.7Bi0.18Er0.02 square 0.1TiO3 (BNT-BT-SBET), is developed with an adiabatic temperature change (Delta T) of 0.7 K under an electric field (E) of 60 kV/cm at room temperature, an anti-Stokes fluorescence cooling, and a maximum optical Tsensitivity of 0.0055 K-1 at 522 K. Interestingly, the electrocaloric response reaches a saturation at permittivity shoulder T of 100 degrees C; meanwhile, the maximized emission intensity of H-2(11/2) -> I-4(15/2) occurs. T- and E-tunable enhancement of H-2(11/2) -> I-4(15/2) emission intensity is due to the population inversion from the (4)S(3/2 )to H-2(11/2) states caused by an incoherent regime consisting of FE phase and polar nanoregions in a relaxor matrix. (C) 2020 Optical Society of America