An Eu/Tb-codoped inorganic apatite Ca5(PO4)3F luminescent thermometer

A new Eu/Tb-codoped inorganic apatite Ca5(PO4)3F luminescent thermometer has been targeted. Under ultraviolet irradiation, the Ca5(PO4)3F:Tb3+/Eu3+ samples exhibit a blue-light emission of the host matrix which might originate from the CO2− radical-related defect produced by Cit3− groups, as well as the typical green emission band of the Tb3+ ions, and a red-light emission of Eu3+. These lanthanide-based thermometers (Ca5(PO4)3F:Tb3+/Eu3+) exhibit different sensitivities ranging from different temperatures based on two emissions of Tb3+ at 548 nm and Eu3+ at 621 nm. The temperature-dependent luminescent intensity ratios ITb/IEu can be optimized by the controlled relatively doping of different amounts of Tb3+ and Eu3+ ions.