Research Article

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.