Preparation and luminescence properties of NaYF4:Yb3+, Er3+ powder by microemulsion method

Ytterbium(III), erbium(III) co-doped sodium yttrium fluoride (NaYF4:Yb3+, Er3+) powder were prepared by microemulsion method. CTAB(Cetyltrimethyl ammonium bromide), n-butyl alcohol, n-octane and water were selected as the microemulsion system. The influence of NaF/Y3+ ratio, reaction temperature, reaction time, pH value, aging time, and heat treatment on phase formation, luminous efficiency and the particle size were studied. The results indicate that α-NaYF4:Yb3+, Er3+ samples can be obtained at 140°C for 24 h with the optimal pH=5~6, and β-NaYF4:Yb3+, Er3+ samples can be obtained at 160°C for 60 h with the optimal pH=1~4. The particle sizes of α-NaYF4:Yb3+, Er3+ and β-NaYF4:Yb3+, Er3+ are 200 nm and 1 μm, respectively. Excited by 980 nm LD, the samples emit bright green light peaking at 521, 529, 541, 549 nm, and 541 nm is the strongest.