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

Figure 4

The CIE chromaticity diagram of Y₂O₃ nanoparticles doped with (a) 20% Yb, 2%Er (0.6611, 0.3357); (b) 20% Yb, 2% Ho (0.3884, 0.6026).