Synthesis and visible-near-infrared photoluminescence emission of Er3+- doped LnP5O14 (Ln = La, Gd) ultraphosphates

Er3+-doped LnP(5)O(14) (Ln = La, Gd) ultraphosphates were synthesized via solid state reaction. The phase purity and the structure of samples were characterized by the X-ray powder diffraction (XRD) and the Fourier transform infrared spectroscopy (FTIR). The optical properties were investigated by analysis of the photoluminescence emission spectra recorded in 430-900 nm and 1450-1600 rim wavelength range at room temperature. Upon visible excitation, the Ln(1-x)P(5)O(14):xEr(3+) (Ln = La, Gd; x = 1-5%) phosphors exhibit bright green emission bands, corresponding to transitions from the H-2(11/2) and S-4(3/2) erbium levels to the I-4(15/2) ground state and week red luminescence related to the F-4(9/2) -> I-4(15/2) transition. A strong luminescence at 1.53 nm in the infrared (IR) region due to I-4(13/2) -> I-4(45/2) transition has been observed in Ln(0.95)P(5)O(14:)0.05Er(3+) (Ln = La, Gd) phosphors under the excitation by 488 nm laser light. The experimental results suggest that Er3+ activated ultraphosphates hosts are useful for solid-state lasers applications.