Formation and down/up conversion luminescence of Ln~(3+) doped NaY(MoO_4)_2 microcrystals

摘要

NaY(MoO_4)_2 microcrystals with different morphologies including spherical, rhombic, sheet-like, and rectangular plate-like morphologies have been successfully synthesized via a simple hydrothermal method by varying the molar ratios of Y(NO_3)_3/Na _2MoO_4 and pH values of the resultant solutions. NaY(MoO_4)_2 was demonstrated to be a good host material for different lanthanide ions. In the up-conversion luminescence spectrum of NaY(MoO_4)_2:Yb~(3+)/Er~(3+) under 980 nm excitation, the green emissions (~2H_(11/2)/~4S _(3/2) → ~4I_(15/2)) were observed and the red emission (_4F~(9/2) → _4I~(15/2)) almost disappeared. The CIE chromaticity coordinates of NaY(MoO _4)_2:Yb~(3+)/Er~(3+) were calculated to be (0.27, 0.65). In the up-conversion luminescence spectrum of NaY(MoO _4)_2:Yb~(3+)/Tm~(3+), the ~1G_4 → ~3H_6 as well as ~3F_3 → ~3H_6 emission was observed and the CIE chromaticity coordinates of NaY(MoO_4) _2:Yb~(3+)/Tm~(3+) were calculated to be (0.25, 0.24). The down-conversion luminescence properties of NaY(MoO_4) _2:Eu~(3+) were studied in detail. In addition, the decay lifetimes at the ~4S_(3/2) (Er~(3+)), ~1G_4 (Tm~(3+)), and ~5D_0 (Eu~(3+)) states were determined to be 5.63 μs, 19.76 μs, and 487.39 μs, respectively. This journal is