Fabrication and Luminescence Properties of Rare Earth/Transition Metal Ions-Doped Aluminate Red Phosphors

Abstract: Aluminate phosphor presents its high quantum efficiency, good color rendering, wide excitation scope and emission in visible region, which makes it to be one hot spot of researches. The study of blue/green aluminate phosphor is widely reported, however, red aluminate phosphor is paid less attention to investigated. The luminescence efficiency of single-doped activator is not high and the brightness is inadequate. In this condition, a second activator is needed to be added. On the basis of the consideration, a series of aluminate phosphor are investigated to enhance and improve luminescence properties of red aluminate phosphor by introduction of the second activator or auxiliary.By solid state reaction method and solution assisting calcination method, a series of transition metal/rare-earths ions-doped aluminate phosphors were synthesized respectively. The preparation processes are studied and analyzed. The phases, luminescence properties, morphology and size of samples were characterized by X-ray diffraction (XRD) analysis, spectroscopic analysis and scanning electron microscopy (SEM) respectively. The thesis consists of three following parts.1. The luminescence properties of Bi~(3+) -doped LiAlO_2:Fe~(3+) and Ce~(3+) -doped in LiAlO_2:Fe~(3+) are studied respectively. It is found that by Bi~(3+) -doped, the luminescence intensity of LiAlO_2:Fe~(3+) phosphor is not only improved, but the emission spectra are broadened. In energy transition process, Ce~(3+) ion plays a role of sensitization to Fe~(3+) ion. The most optimum ions-doped concentration and the parameters of process are determined respectively.2. The luminescence properties of B~(3+) -doped LiAl_5O_8:Fe~(3+) phosphor are studied. Compared with LiAlO_2:Fe~(3+) phosphor, LiAl_5O_8:Fe~(3+) phosphor emits bright red light, the emission spectra appears blue shift. B~(3+) ion substituting for partial Al~(3+) ion in LiAl_5O_8 can enhance luminescence intensity of LiAl_5O_8:Fe~(3+) phosphor. B~(3+) -doped LiAl_5O_8:Fe~(3+) not only reduces the reaction temperature, but also makes more pure crystals formed. It is an efficient way to regulate the crystal field around Fe~(3+) ion to change luminescence intensity of Fe~(3+) ion by B~(3+) ion-doped. The most optimum doping content of B~(3+) ions and the parameters of preparation processes are determined respectively.3. The luminescence properties of B~(3+) -doped and B~(3+),Li~+ co-doped SrAl_2O_4:Eu~(3+) are studied respectively. Compared with LiAl_5O_8:Fe~(3+) phosphor, the luminescence spectra of B~(3+) -doped SrAl_2O_4:Eu~(3+) phosphor are broadened. The luminescence intensity of SrAl_2O_4:Eu~(3+) phosphor is improved by B~(3+) ion-doped. Furthermore, the luminescence intensity is improved furtherly by Li~+ ion-doped. The luminescence mechanisms of two kinds of dopants are discussed respectively. Finally, the most optimum B~(3+) and Li~+ -doped concentration and the parameters of process are determined respectively…
Key words: aluminate; doped; luminesce intensity; phosphor; concentration

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