Dual-mode green emission and temperature sensing properties of rare-earth-element-doped biphasic calcium phosphate composites

Abstract

This work presents a novel multifunctional material synthesized by hydroxyapatite/ β-tricalcium phosphate (HA/β-TCP) doped with Er-Yb-Mo ions (using hydrothermal method) and its characterization, showing a peculiar property of green dual-mode emissions (up and down-conversions). It was found that the obtained material exhibits an intense green emission (510–560 nm) both via up-conversion (excited by 975 nm) and down-conversion (excited by 379 nm), which depend on the Mo6+ contents. Particularly, compared with the free-Mo6+ sample, the green emission intensities of the samples doped with 5% Mo6+ mol are 50 and 35 times higher for UC and DC emissions, respectively. Furthermore, the temperature sensing property of the HA/β-TCP: Er-Yb-Mo composite is investigated by fluorescence intensity ratio (FIR) technique, showing a high and competitive sensitivity with a maximum value of 0.0064 K−1 at 403 K. The results indicated that the HA/β-TCP: Er-Yb-Mo phosphor can be useful for high-temperature-sensing applications.