Synthesis And Luminescence Properties Of Phosphor Doped With Rare Earth Ion For White LED

In the21st century,white light emitting diodes are considered as the forthgeneration of lighting sources, which most likely will replace incandescent lamps andfluorescent lamps, because the advantages of long life, energy saving, high luminousefficiency and so on. Currently, using a near ultraviole chip coated red, green and bluephosphors has become the emphasis direction to generate white LED. High tempera-ture solid-state method is a traditional fluorescent material synthesis method, thepreparation method is simple and easy to succeed.This paper mainly introduced about white phosphor with excellent luminescentproperty under the different experimental conditions. This thesis not only explores thephosphor of SrAl2Si2O8:Eu2+but also Sr5SiO4Cl6:Eu2+. The main research consist ofthe influence of time, temperature, solvent and other factors on luminescent property,but also adopts different characterization methods, such as fluorescence spectrometer(FL),Scanning electron microscopy (SEM), X-ray diffraction (XRD), TG-DTA, FT-IRand so on, to analyze the performance and structure of the phosphor of SrAl2Si2O8:Eu2+and Sr5SiO4Cl6:Eu2+.1. The experiment synthesized SrAl2Si2O8:Eu2+in a reducing atmosphere C by asolid state method, and performed X-ray diffraction (XRD), spectrum and SEMmeasurements testify the crystal structure and luminescent properties. Via those testresults investigated in detail the factors those affect the structure and luminescenceproperties, including sintering temperature, the doped of Eu2+and the flux H3BO3. Inconclusion, the optimal sintering temperature is1300℃, the concentration of H3BO3is3.0wt%, the concentration of Eu2+is2.5mol%. SrAl2Si2O8:Eu2+is a new kind ofblue emitting phosphor excited by UV LED, with stable property and simplepreparation，and bid fair to find application as blue emitting phosphor of tri-colorphosphor for white LED.2. Rare earth ion doped Sr5SiO4Cl6:Eu2+phosphor was synthesized by hightemperature solid state method under a reductive atmosphere. The crystalline phasewas tested with X-ray diffraction (XRD). The morphology of sample was observed bySEM. Use fluorescence spectrometer to examine its excitation and emission spectra. The optimal concentration of the Eu2+was decided, the effects of the soaking time,the synthetic temperature and the flux were also studied. The result shows thatSr5SiO4Cl6crystal belongs to monoclinic system, the optimal concentration of the Eu-2+is1.5mol%, the most suitable soaking time is5h, the best synthetic temperature is815℃, and the best content of H3BO3is1.5wt%. Sr5SiO4Cl6: Eu2+phosphor shows anefficient broad band absorption around380nm, with matches well with the commer-cial NUV light-emitting chips, moreover, it shows a broad emission band from400nmto550nm under the380nm excitation, two obvious peaks at410nm and445nm can beobtained through lawrence multi-peak fitting. Therefore, Sr5SiO4Cl6:Eu2+phosphor isa promising blue emitting component for UV light emitting chips white LED.All the two host materials doped with rare earth Eu2+can be effectively excitedwith the UV-NUV regions which agree with the emission wavelength of LED chip-s.Therefore they can be considered as potential UV-NUV LED phosphors.