Power driven tunable white upconversion luminescence from Lu2TeO6 tri-doped with Yb3+, Tm3+ and Ho3+

Abstract

Lu₂TeO₆ (LTO) doped with Yb³⁺, Tm³⁺ and Ho³⁺ ions has been synthesized by solid state reactions. Powder XRD and Rietveld refinement data confirmed that these compounds have a hexagonal structure with space group P321 (no. 150). The SEM images have shown the average size of the particles was smaller than 1 μm. Upconversion (UC) properties of the co-doped Yb,Tm:LTO and Yb,Ho:LTO as well as the tri-doped Yb,Tm,Ho:LTO were investigated under the excitation of a 976 nm laser diode. The blue, green, and red UC emissions were realized and successfully combined to yield white UC luminescence in the Yb,Tm,Ho:LTO system. The light color was studied in the framework of the 1931 CIE system. For the Yb,Tm,Ho:LTO, the UC light color can be continuously tuned in the white range by adjusting the pump power. The results have suggested that the Yb,Tm,Ho:LTO has potential as a phosphor for UC based white lighting and optoelectronic devices.