Research On Synthesis And Fluorescence Properties Of Rare Earth Ion Doped Novel Oxide-based White LED Phosphors

White light LEDs has been considered to be the next generation lighting source due to its many advantages such as high efficiency, long lifetime, small volume, low power consumption, environment-friendly characteristics. At present, the method of fluorescent transformation is the main way is to manufacture white LED. Meanwhile, phosphors are the central part. Oxide-based phosphors attract researcher’s attention because of their stable chemical properties and excellent luminescence properties. In this paper, the rare earths (Eu3+, Eu2+, Dy3+) doped garnet structure, perovskite structure, phosphate and silicate phosphors were synthesized by high temperature solid method. The crystal structure, morphology characteristics, fluorescent properties and related mechanisms were investigated.The main studies and results are listed as follow:(1) A series of Eu2+, Dy3+ doped (Ca,Sr)7(SiO3)6Cl2 phosphors were prepared by self-flux menthod. The relationships between structure and optical properties were investigated by XRD and PL spectra. The collaborative luminescence behavior and mechanism of Eu2+, Dy3+ doped (Ca,Sr)7(SiO3)6Cl2 were analysised. The quantum efficiency of composition-optimized (Ca,Sr)7(SiO3)6Cl2:10% Eu2+,3% Dy3+ was also detected.(2) A series of novel red phosphors Li6ALa2M2O12:Eu3+(A= Ca, Sr, Ba; M= Nb, Ta, Sb) and Ca8La2(PO4)6O2:Eu3+ phorphors were prepared by solid-state method. The relationships between structure and optical properties were investigated by X-ray diffraction, UV-vis absorption spectra and photoluminescence spectra. The lattice by changing ionic of c and d sites is adjusted in garnet structure. The effect on the luminescent properties of Eu3+ by changing the species and radius of ionic at A and B sites in garnet structure was discussed in detail, and their luminous mechanisms were also studied.(3) The single-phase white phosphors NaLa(PO3)4:xDy3+, CaTO3:Dy3+ and CaTO3:Dy3+,Li+ were synthesized by high temperature solid-state method. Their morphologies, structures, optical properties and optimal concentration were analyzed. The substitution of Li+ ions can obviously improve the fluorescence intensity of CaTiO3:Dy3+ phosphor, because the Li+ not only serves as an agent of charge compensation, but also plays the role of cosolvent to increase the crystallinity and improve the crystal field environment of the samples.