Preparation And Property Investigation Of Novel Phosphors For White Light-Emitting Diodes Use

White light-emitting diodes(WLEDs), the next generation solid-state lighting, have wide applications in display devices and optical fiber communication. Among the various phosphors for WLED use, the red-emitting ones adapted to the blue light or UV LED chip are the most commercially potential ones to be developed. In the most inorganic compound, tungsten bronze niobates are chemically and thermally stable, low-cost and structurally versatile. They are potential host materials, and are of great practical and scientific importance. In this study, the high-valence Nb5+ -containing (A1)4(A2)2(C)4Nb10O30 (A1=K,Ba,Sr,Ca;A2=Sr,Ca;C=Vacancy) materials with the structure of tungsten bronze are explored as novel host materials, prepared via solid state reaction. Their X-ray diffraction, ultraviolet-visible absorption spectroscopy and fluorescence spectrum are well characterized. Moreover, several valuable phosphors for WLED use are developed. The main results are as following:1.Novel Sro.3Ba0.7Nb2O6:Eu3+ and Sro.3Cao.7Nb206:Eu3+ phosphors are characterized. They are all intense red-emitting. The intensity of Sro.3Cao07Nb206:Eu3+ phosphor is higher than that of Sro.3Bao.7Nb2O6:Eu3+ phosphor. The I612(5D0-7F2)/I592(5D0-7F1) ratios are both around six. The two best excitation areas are in the ultraviolet range. The intensity of the blue areas is also strong. Such phosphors can be used as red ones for WLED pumped by UV and blue chip.2.Novel ANb2O6:0.3Eu3+(A=Ba,Sr,Ca) phosphors are investigated. BaNb2O6:0.3Eu3+ and SrNb2O6:0.3Eu3+ phosphors are both releasing orange-red light. The CaNb2O6:0.3Eu3+ phosphor is emitting red light. The intensity of CaNb2O6:0.3Eu3+ phosphor is higher than that of BaNb2O6:0.3Eu3+ phosphor and SrNb2O6:0.3Eu3+ phosphor. The intensity of SrNb2O6:0.3Eu3+ phosphor is weakest. The two best excitation areas are both in ultraviolet range. The intensity of the blue areas is also satisfactory. These phosphors have great potential application in WLED pumped by UV and blue chip.3.Novel A2KNb5O15:0.3Eu3+(A= Ba,Sr,Ca) are discovered with intense red emissions under both UV and blue excitations, in the order of Ca2KNbO15:0.3Eu3+> Sr2KNb5O15:0.3Eu3+>Ba2KNb5O15:0.3Eu3+. They are all promising red phosphors used for WLED.