Site selective, time and temperature dependent spectroscopy of Eu3+ doped apatites (Mg,Ca,Sr)2Y8Si6O26

This work concerns the optical properties of alkaline earth yttrium apatites according to the composition AE2Y8Si6O26 (AE=Mg, Ca, Sr) doped with Eu3+, which are materials of interest for LED applications. Using a multistep preparation route, which includes hydrothermal synthesis of precursors for solid state reaction, ceramic samples were prepared and their structural and optical properties characterised. More particularly, this work relates to site-selective spectroscopy, since the compounds comprise two distinguishable crystallographic sites within the host structure, where Eu3+ can be substituted. It also describes the temperature dependent photoluminescence, which thermal quenching temperature (T1/2) for Sr2Y8Si6O26:Eu3+ and Ca2Y8Si6O26:Eu3+ is in the range of 561 K and 591 K respectively, whereas Mg2Y8Si6O26:Eu3+ shows bi-sigmoidal quenching behaviour in the range between 210 and 452 K.