White LED with multi-molybdate red light-emitting properties of fluorescent materials

Title: White LED with multi-molybdate red light-emitting properties of fluorescent materialsAuthor: I Chui provinceDegree-granting unit: Hebei Normal University,Keywords: molybdate;; Eu ~ (3);; light;; solid-state reactionSummary:

White light emitting diode (White light emitting diode, referred WLED) is a new solid-state lighting, with high efficiency, long life, green and small size, fast response, simple structure, etc., known as the 21st century green light. White LED current to achieve the Neodymium Magnets most effective way is to phosphor conversion. But the development of the red phosphor white LED luminous efficiency is low, can not meet the requirements, the need to develop new and efficient white LED with a red fluorescent material.

In this paper, the traditional high-temperature solid-phase method to molybdate as a substrate material, doped with rare earths Eu ~ (3) ion can be prepared by a variety of effective near-UV excitation red phosphor: alkali metal cations Li ~, K ~ doped Na_5Eu (MoO_4) _4 system; oxygen carboxylate anion (PO_4) ~ (3 -), (SO_4) ~ (2 -), (ClO_3) ~ - doped Na_5Eu (MoO_4) _4 and on this basis consider the equilibrium price doping, in introduction of the system Li ~ ion, Cl ~ - ion; LiGd_ (1-x_Eu_x (MoO_4) _2 system and LiGd_ (0.6-x) Y_xEu_ (0.4) (MoO_4) _2 system. and studied reaction conditions and the doping concentration of the system structure and luminescence properties of the sample effects.

For the analysis of different doping ions, different charge compensation of the samples doped with different substrate crystal structure and fluorescent properties, the samples were X - ray diffraction (XRD), scanning electron microscopy (SEM), were characterized by excitation and emission spectra . XRD results show that different from doping Na_5Eu (MoO_4) _4 system samples belong to the class of tetragonal scheelite (Scheelite - like) structure. Different doped LiGd (MoO_4) _2 system of the sample are tetragonal scheelite (Scheelite) structure. Samples of the two systems are space group I41 / a. SEM images show effective help to improve the doping effect of http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets sample crystallinity, morphology modification of the sample. At 395 nm near-UV excitation, all samples Eu ~ (3) of the 5D0 - 7F2 (615 nm) transition emission of red light intensity is higher than the commercial Pink Y_2O_2S: Eu ~ (3) of the emission intensity.

This article about the different doping ions, different substrate doping of rare earth Eu ~ (3) activation of molybdate ion crystal structure and luminescence properties of the basic research, for the white LED red light-emitting materials with the design of new development to provide a value of the theoretical basis.Degree Year: 2010