Synthesis and photoluminescence of host-sensitized MgNb2O6 based phosphors

Abstract

A series of undoped, Dy3+ and Tm3+ singly-doped, co-doped MgNb2O6 phosphors were prepared by solid-state reaction. Powder X-ray diffraction (XRD), photoluminescence excitation (PLE) and emission (PL) spectrum under UV and VUV excitation, decay lifetimes and CIE chromaticity coordinate were employed to explore the luminescence properties of synthesized phosphors. MgNb2O6 host exhibits a broad emission band from about 350 to 650 nm centered around 451 nm under the UV excitation of 275 nm originating from the NbO6 octahedral groups. Its photoluminescence presents the temperature quenching behavior under VUV excitation. The yellow phosphor MgNb2O6:Dy3+ and blue phosphor MgNb2O6:Tm3+ show the dominant emission peak at 583 nm (4F9/2-6H13/2) upon 275 nm excitation and at 484 nm (1G4-3H6) upon 274 nm, respectively. The Dy3+ and Tm3+ co-doped MgNb2O6 phosphors exhibit tunable colors varying from yellow to warm-white with the emission peak at 583 nm (4F9/2-6H13/2) as concentration of Tm3+ increased. With the increasing concentration of dopant ions, the value of average decay times (t) of characteristic emission of activators monotonously decreases. The stability of representative MNO:0.045Dy3+, 0.02Tm3+ phosphor was investigated base on measurement of temperature-dependent emission spectra. Considering the easy synthesis and special luminescence properties of MgNb2O6-based phosphors, it is extraordinarily meaningful to study for luminescent materials as a fundamental research.