Enhancing upconversion of Sc2Mo3O12:Yb/Ln (Ln = Er, Ho) phosphors by doping Ca2+ ions

Lanthanide doped Sc2(MoO4)3 upconversion (UC) crystals showed distinct negative thermal quenching effect, which show promising applications in the temperature sensing field. However, it is still valuable to develop novel routes to enhance the room temperature UC intensity. Herein, the UC intensity of the Yb/Er (Ho) doped Sc2Mo3O12 crystals were significantly enhanced by doping Ca2+ ions. The incorporation of Ca2+ ions can break the crystal symmetry around the activators and then promote the 4f-4f transitions followed by the enhanced UC. Especially, the UC intensity of the Sc2Mo3O12:20Yb/1Ho/20Ca was about 100 times than that of Sc2Mo3O12:20Yb/1Ho phosphors. Furthermore, the thermally couple levels based temperature sensing performance was improved after doping Ca2+ ions. Our results may promote the exploration of novel scheelite structural compounds with superior UC properties.