Hydrothermal Synthesis and Tunable Multicolor Upconversion Emission of Cubic Phase Y₂O₃ Nanoparticles

Figure 3

Upconversion luminescence spectra of Y₂O₃ nanoparticles doped with (a) 20% Yb, 2% Er; (b) 20% Yb, 2% Ho. (c) Simplified energy-level diagram of Yb³⁺/Er³⁺ and Yb³⁺/Ho³⁺ doped Y₂O₃ samples. The insets of (a) and (b) are the corresponding digital photographs of the water solutions of these nanoparticles.

(a)

(b)

(c)