Preparation of Eu 3+ doped Al 5 BO 9 red phosphor by a facile thermal conversion method and its enhanced luminescent pro
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new red-emitting phosphor, Eu31 doped Al5BO9, was prepared for the first time by calcining the precursor of K2[Al(B5O10)]4H2O:Eu31 which was synthesized by a facile hydrothermal route. The obtained samples were characterized by energy dispersive x-ray spectrometer, x-ray powder diffraction, IR, scanning electron microscopy, photoluminescence, and photoluminescence excitation spectrum (PLE). Moreover, the influences of Eu31 doping concentration, calcination temperature, and calcination time on the luminescence properties of Al5BO9:Eu31 phosphor were also investigated. The phosphor with optimal luminescent intensity and the higher red/orange ratio was obtained by sintering the precursor at 1300 °C for 5.5 h, with 5% doping concentration, in which its luminescent decay lifetime and quantum efficiency were also measured. It is also found that the phosphor prepared by conventional solid-state reaction method exhibits the dominant transition at 591 nm (orange) with the lower color purity, while the phosphor prepared by the present precursor method exhibits the dominant transition at 615 nm (red) with the higher color purity, which indicates that this is a good method for preparing Al5BO9:Eu31 red phosphor.
I. INTRODUCTION
During the past years, many borates were chosen as host lattices for phosphors because of their large band gap, high thermal stability, high luminescence efficiency, and low cost.1,2 Aluminum borate material with excellent mechanical properties and chemical inertness is a suitable host material for high efficiently optical materials.3 So many researchers have used some aluminum borates as the host lattices for phosphors, like M2Al2B2O7 (M 5 alkali metals),4 Al18B4O33,5 and MAl3(BO3)4 (M 5 Y, Gd),6 and so on, which were activated by trivalent rare-earth ions. Among the trivalent rare-earth ions, Eu31 ion is an excellent activator in a great amount of phosphors which exhibit high quantum efficiency in red region.7 The hydrous aluminoborate K2[Al(B5O10)]4H2O was synthesized under hydrothermal conditions, and its structure is characterized as an anionic [Al(B5O10)]n2n open framework constructed by B5O10 units and AlO4 tetrahedra.8 As far as we know, aluminum borate Al5BO9 was prepared by conventional solid-state reaction,9 and there is only one report on the Al5BO9 based phosphor, namely Al5BO9:Sm31 phosphor prepared by the sol–gel method.10 If the host material and the activator concentration are fixed, the photoluminescence (PL) efficiency strongly Contributing Editor: Winston V. Schoenfeld a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.148 J. Mater. Res., Vol. 31, No. 10, May 28, 2016
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depends on the physical properties of phosphor materials, such as the surface area, the crystallinity, the phase purity, and the distribution of activator in the host matrix. Such physical properties are influenced by the preparation method and reaction parameters.11 Since Al5BO9 is a chemically and thermally stable matrix, dev
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