Upconversion white luminescence of TeO2:Tm3+/Er3+/Yb3+ nanoparticles

In this study, TeO 2 :Tm 3+ /Er 3+ /Yb 3+ nanoparticles had been successfully prepared via a hydrothermal process. All the as-prepared TeO 2 :Tm 3+ /Er 3+ /Yb 3+ nanoparticles showed the blue (476   nm), green (525   nm, 545   nm) and red (667   nm) emissions under 980   nm excitation, which were attributed to the 1 G 4   →   3 H 6 (Tm 3+ ), 2 H 11/2 , 4 S 3/2   →   4 I 15/2 (Er 3+ ) and 4 F 9/2   →   4 I 15/2 (Er 3+ ) transitions, respectively. The decay lifetime of blue, green and red emissions were 40   μs, 46   μs and 89   μs, respectively. The combination of blue, green and red emissions resulted in the white luminescence which was intense and visible to the naked eyes. The calculated CIE color coordinates of TeO 2 :Tm 3+ /Er 3+ /Yb 3+ nanoparticles fell well within the white region and changed little with the incident pump power from 1.75   W/cm 2 to 16.13   W/cm 2 , which indicated that the materials may have potential applications in the fields of three dimensional displays, back lighting, white light sources, and so on.