Study On Synthesis And Properties Of Red Phosphor Used In White LED

White LED has many advantages,such as energy saving,long life and fast response,so as to accelerate its development in the field of lighting.The white LED is the main way of blue chip and yellow combination,the main problem is the existence of higher color temperature,color rendering index is low.Silicate matrix has good chemical stability and temperature stability,and have strong absorption to ultraviolet,near ultraviolet and blue light.Eu³⁺ has two relatively strong excitation peaks in the ultraviolet region?about 395 nm?and the blue light region?about 465 nm?,which can be assigned to the UV or blue LED chips.Therefore,taking Eu³⁺as activator,the synthesis of stable red phosphor has become the focus of the study.Ca₂MgSi₂O₇:Eu³⁺ red phosphor is prepared by high temperature solid state method.The main emission peak of the sample is located at 618 nm,which indicates that the electric dipole transition plays an important role in the emission of red light.The fluorescence intensity of doped Sr₂+ is 4.3 times than no doped Eu³⁺.The excitation spectra of Eu³⁺and Sm³⁺codoped are close to 400 nm.The mechanism of energy transfer from Sm³⁺ to Eu³⁺ and Gd³⁺ to Eu³⁺ was revealed.Sr₂Al₂SiO₇:Eu³⁺ red phosphor is prepared by high temperature solid state method.The optimum calcination temperature is 1150 ?,the particle size of the sample is better,and the morphology of the sample is the best,and the shape is regular.The particle size is about 2 ?m.Under the excitation of 394 nm wavelength,the main emission peak is at 617 nm,which indicates that the5D0-7F2 transition plays a major role in the emission of red light.With the addition of Mo⁶⁺ and W⁶⁺,the fluorescence intensity was significantly enhanced.Li₂SrSi O₄:Eu³⁺red phosphor is prepared by high temperature solid state method.The introduction of charge compensation agent can obviously improve the luminescence properties of samples,and the effect of doping Cl-is the best.Doped Mo⁶⁺ fluorescence intensity significantly enhanced color coordinates of?0.657,0.342?,with commercial phosphor?0.631,0.350?compared to Y2O2S:Eu³⁺,and the red color values?0.67,0.33?closer.CaMoO₄:Eu³⁺,0.04Li⁺ red phosphors is prepared by hydrothermal method.Red emission of 616 nm at 395 nm wavelength excitation.The doping of Sr₂+ and W⁶⁺ can effectively improve the fluorescence intensity.After Eu³⁺and La³⁺codoping,La³⁺can be used as sensitizer to provide energy for Eu³⁺,and then the fluorescence intensity is enhanced.