The Research Of Synthesis And Properties Of Red Luminescent Materials By LED

Along with society's progress and development,energy conservation and environmental protection has gradually become the main topic of society concern.Because the traditional lighting system has many disadvantages,such as big energy consumption,contaminate the environment and so on,the new lighting system is urgently needed.White light emitting diodes as the fourth generation solid-state lighting has been intensively concerned by more and more researchers.As an important supplement of WLED luminescence system,red-emitting phosphor is one of the key research directions.But many of materials have low luminescence efficiency and less chemical stability,so it is important to search red phosphors matrix materials with good physical and chemical properties stability and good optical properties.The luminescent material precursor was prepared by electrospinning method,and one dimensional CaYAl₃O₇: Eu³⁺,Sm³⁺ phosphor was obtained after further calcination.Thermogravimetric differential thermal analysis?TG-DTA?was used to analysis the mechanism for the formation of one-dimensional material.X-ray powder diffraction was used to analysis crystal structure of the material.Scanning electron microscopy was used to characterize morphology of the material,and fluorescence spectroscopy was used to analysis fluorescence properties of the material.The results show that the materials obtained after being calcined for 3h at 800°C have good uniformity,and the diffraction peaks of the samples are in good agreement of standard card?JCPDS: 49-0605?.The luminescent materials emit red emission located at 617nm when were excited under 393nm,and when the Eu³⁺ doping amount to 13mol%,the Sm³⁺ doping amount to 10mol%,the luminous intensity of the material is highest.The CaNb₂O₆:Eu³⁺,Gd³⁺ powder were prepared by high temperature solid state reaction method.The influence factors which are calcination temperature,calcination time and doping concentration of Eu³⁺ and Gd³⁺ were studied.The research result show that the best calcination temperature is 1000°C,the best calcination time is 5h,and the optimum doping concentration of Eu³⁺ and Gd³⁺ are 8mol% and 6mol%,respectively.Preparation of phosphor optimal excitation wavelength of 466nm,best emission wavelength of 613nm.Eu³⁺ doped Ca₃Ti₂O₇ was prepared by the sol-gel method.The structure of prepared samples was characterized by X-ray diffraction?XRD?and the surface morphology was studied by scanning electron microscopy?SEM?,the color coordinates and luminescence properties were studied.By the fluorescence analysis,we find that the sample showed the strongest luminescene intensity when the europium ion doping concentration of 13mol%,the sintering temperature is 1000°C,and the holding time is 3h.And the best excitation wavelength is 398nm,belonging to UV excitation,and the best emission wavelength is 616nm which located in red laser.