| Traditional incandescent bulbs and fluorescent lamps are fragile,they lead to mercury contamination and great power consumption.However white-LED is eco-friendly, due to its long lifespan and smallsize, it became the main selection of illuminating devices.Currently, generating WLED has three forms: First type is yellowphosphor excited by blue-ray match the remainder of blue-ray toengender the WLED. In this form, the color rendering index and thecolor restoration is poor because emission color varies with the drivingvoltage and the thickness of phosphor. Second type is near-UV excitesRGB tricolor phosphor, While it is difficult to control the mostappropriate color proportion. The last form is the red, green and bluelight chip assembled to produce white light. In this form chromaticaberration caused by temperature is inevitable, at the same time, thecost of chips is high. Therefore, developing a new type of phosphorwhich is a single full color used to W-LED has great significance.In this thesis, Sr32MgSi2O7: Ce+, Tb3+, Mn2+phosphors weresynthesized by high temperature solid method and microwave-assistedgel-combustion method. Crystallographic characteristics, morphology,size and distribution of the phosphors were preliminary studied.Spectral properties of the phosphor samples were tested and analyzed.The color temperature, color coordinates, color rending index andfluorescence lifetime of the phosphor samples were analyzed throughsimulation and calculation.Compared with the crystal properties, luminescent properties,particle size and distribution properties in different synthesizing method,Sr2MgSi2O3++7: Ce, Tb3, Mn2+phosphors synthesized by microwaveassisted gel-combustion method has the better performance than the phosphors produced through high temperature solid method. Themorphology was completed spherical-like particle, particle size rangesfrom1to3microns.Monitored by380nm blue light, The Sr3+2MgSi2O7: Cephosphorspresent wide bimodal spectrum excitation at277nm and329nm.Excited by360nm UV, Sr2MgSi2O7: Ce3+phosphors present acontinuous emitting broadband around373nm, which is attributed toCe3+ions5d04f1â†'5d14f0transition.Monitored by545nm green light, Sr2MgSi2O7: Tb3+phosphorshave a multimodal broad band in the UV and blue regions, its strongestpeak located in369nm. Excited by360nm UV, Sr3+2MgSi2O7: Tbphosphors have a multimodal broad band form400nm to650nm, thestrongest peak located in545nm. It shows yellow-green light-emitting,because of the poor blue and red emission in the emission spectra.Motivated by365nm UV, Sr2MgSi2O7: Ce3+, Tb3+phosphorspresent blue, light, red light full-color-emitting in the visible range.Sr+2MgSi2O3+7: Ce, Tb3phosphors is manifested as blue-greenluminescence, because of weaker red light. Fixed one of Ce3+and Tb3+ions, The characteristic emission peaks corresponding to Ce3+and Tb3+ions are changed, proved that energy transfer occurs between Ce3+andTb3+ions.Excited by360nm UV, Sr2MgSi32O7: Ce+, Mn2+phosphors have abimodal launch, one of which is bright blue luminescence band at380nm, the other is red wide-band luminescence spectrum at680nm. Withthe increase of Mn2+content doped, the luminescence color presentredshift, red ratio gradually increased, meanwhile, The emission peakintensity corresponding to Ce3+is reduced. It is proved that energytransfer occurs between Ce3+and Mn2+.Effectively excited by338nm UV, Sr3+2MgSi2O7: Ce, Tb3+, Mn2+phosphors appear blue, light, red light full-color luminescence, in thevisible range. In the matrix compounds, Ce3+transfer energy to Tb3+andMn2+. Sr2MgSi2O7:0.03Ce3+,0.05Tb3+,0.03Mn2+phosphor’s colorcoordinates located at (x=0.3178, y=0.3014) in CIE, where is very close to the standard light, So it is considered to be a full-color singlematrix W-LED phosphor which can match UV chip effectively. |
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