Fig. 8From: Synthesis and Luminescence Properties of Water Soluble α-NaGdF4/β-NaYF4:Yb,Er Core–Shell NanoparticlesPhotoluminescence decay curves of the a 2F5/2 level of Yb3+, b 4F9/2 level of Er3+, c 4F9/2 level of Er3+, and d 2H9/2 level of Er3+ in the heterogeneous core/shell α-NaGdF4/β-NaYF4:Yb, Er crystals with varied reaction time (black: 2 h, red: 6 h, blue: 12 h, pink: 24 h)Back to article page