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

Lanthanide doped Sc 2 (MoO 4 ) 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 Sc 2 Mo 3 O 12 crystals were significantly enhanced by doping Ca 2+ ions. The incorporation of Ca 2+ 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 Sc 2 Mo 3 O 12 :20Yb/1Ho/20Ca was about 100 times than that of Sc 2 Mo 3 O 12 :20Yb/1Ho phosphors. Furthermore, the thermally couple levels based temperature sensing performance was improved after doping Ca 2+ ions. Our results may promote the exploration of novel scheelite structural compounds with superior UC properties.