Defects levels and VUV/UV luminescence of Ce3+ and Eu3+ doped chloroapatite phosphors M5(PO4)3Cl (M = Ca, Sr, Ba)

Abstract Recently, phosphors like lanthanide-ion-doped chloroapatite M5(PO4)3Cl (M = Ca, Sr, Ba) are successfully captured intensive investigations due to their potential applications in UV-LED and solid-state lasers devices. However, how to improve its luminescent efficiency or explore its potential applications are still a challenge so far. It is largely due to the defect levels induced by those lanthanide ions, especially the knowledge of their positions relative to the host bands, is unclear, which is the first requirement to understand the mechanisms of their luminescent properties. In this work, we show how the quenching of Ce3+/Eu3+ doped chloroapatite materials responds to their position relative to their conduction bands through thermoluminescenc (TL), photo-spectroscopic measurements and first-principle calculations in detail. We believe this work would provide a comprehensive understanding the underlying luminescent mechanism of the lanthanide-ion doped chloroapatite M5(PO4)3Cl (M = Ca, Sr, Ba) so far and also give a valuable guidance for the development of high efficient new chloroapatite phosphors in the future.