Dual-mode photoluminescence, temperature sensing and enhanced ferroelectric properties in Er-doped (Ba0.4Ca0.6)TiO3 multifunctional diphase ceramics

Dual-mode phosphors, Er3+ doped Ba0.4Ca0.6TiO3 ferroelectric diphase ceramics, were prepared by a conventional solid-state reaction method and their phases, microstructure, photoluminescence, ferroelectric and dielectric properties were investigated. The ceramics exhibit up-conversion and down-conversion emission of 550 nm light excited by a near-infrared (980 nm) light and a 487 nm blue light, respectively. The related photoluminescence mechanism has been discussed. In up-conversion emission, the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of the Er3+ ion portray a temperature dependent behavior and have been used for optical temperature sensor using the fluorescence intensity ratio method. The maximum sensitivity is found to be 0.0033 K−1 at 483 K in the temperature range of 103-573 K. Together with the enhanced ferroelectric properties and good dielectric properties, these ceramics should be one of the promising candidates for multifunctional optoelectronic applications.