White light-emitting diodes doped with rare earth phosphor synthesis and properties
White light emitting diodes (WLEDs) With high efficiency, long life, high stability and small size, and many other advantages are widespread attention.Solid as a potential light source, the light efficiency and color parameters, and the price is the most important indicator.The decision of these indicators are LED-chip and the fluorescent coating on the chip conversion material.The study is to synthesis of some can be effectively excited blue or near UV phosphor new.Select Li2SrSi04: Eu2 + and ZnMoO4: Eu3 + phosphor for the two types of study, by doping to improve the brightness of such phosphors, and tuning the excitation and emission wavelengths.
Li2Sr0.995SiO4: 0.005Eu2 + is a Blu-ray can be (400-480 nm) effectively excited, emitting around 580 nm peak in the yellow phosphor.Our results show that: by PO43-and SO42-doping could significantly increase the luminous intensity, the optimum composition of Li2Sr0.995 (SiO4) 0.9775 (P04) 0.03:0.005 Eu2 + and Li2Sr0.995 (SiO4) 0.945 (SO4) 0.11:0.005 Eu2 +.Excited at 460 nm, their emission intensity are Li2Sr0.995SiO4: 0.005Eu2 + | 1.8-and 2.2-fold.And SO42-doping can make the strongest excitation and emission spectra peaks were 412 and 580 nm by the red shift 460 and 610 nm, blue LED chip to make it more suitable for red excitation and emission.The Pr3 + doped Li2Sr0.995SiO4: 0.005Eu2 + also can enhance their blue (452 nm) excitation efficiency and in the red region (610 nm) emission intensity.And the proof of Pr3 + doped Li2SrSiO4 is a single blue LED that can be effectively excited red phosphor.
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Can be synthesized blue (466 nm) and near-UV (395 nm) while effectively stimulating the ZnMoO4: Eu3 + red phosphor line (emission peak 615 nm).Our goal is through incorporation of Li + as the charge compensation, the incorporation of (Bi3 +, Sm3 +) or (La3 +, Y3 +, Gd3 +) to replace part of the Zn2 +, thereby increasing the luminous intensity of the phosphor and the excitation peak width.Prove that the addition of Li + ions significantly increase the brightness of the powder, the best ratio of Zn0.5MoO4: Eu3 +0.25 Li +0.25; amount of Bi3 +, Gd3 + and Sm3 + can further improve the incorporation of luminous intensity, and the incorporation of Sm3 +excitation peak to 395 nm, are significantly broadened.Accordingly, the performance has been excellent Zn0.454MoO4: Eu3 +0.25 Li +0.25 Bi3 +0.04 Sm3 +0.006 and Zn0.44MoO4: Eu3 +0.25 Li +0.25 Gd3 +0.06 phosphor.The red phosphor excitation wavelength coincides with the current Blu-ray and near-UV LED chip light match, in the blue and near UV LED chips based on the great white light LED assembly potential applications.
