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Pr~(3+)-doped Li_2SrSiO_4 red phosphor for white LEDs 总被引:1,自引:0,他引:1
Novel red phosphors,Li2Sr1-1.5xSiO4:xPr3+(x=0.002,0.003,0.004,0.005,0.006 and 0.008),were synthesized by conventional solid state reaction and the luminescent properties were investigated.The as-prepared phosphors showed red emission at 610 nm under excitation of blue light at 452 nm,indicating that they were promising candidates for red phosphors in the fabrication of white LEDs via blue LED chips.Their excitation bands at 452,476 and 487 nm were attributed to transitions of 3H4→3P2,3H4→3P1+1I6,3H4→3P0 of Pr3+ ion.The red emissions at 606 and 610 nm were originated from the 3P0-3H6 and 1D2-3H4 transitions of Pr3+.The optimum doping concentration of Pr3+ in Li2Sr1-1.5xSiO4:xPr3+ was determined to be x=0.004.With the concentration of Pr3+ over x=0.004,the fluorescence intensity of Li2Sr1-1.5xSiO4:xPr3+ decreased,indicating the concentration quenching occurred. 相似文献
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Green light-emitting Ba2SiO4:Eu2+ phosphors co-doped with La or Y were synthesized by conventional solid-state reaction technique in reductive atmosphere (a mixture of 5% H2 and 95% N2). The results showed that the co-doping of La and Y could greatly enhance the fluorescence intensity of Ba2SiO4:Eu2+ phosphors. The optimum doping concentration expressed by the x value in (Ba0.985-1.5xREx)2SiO4: 0.03Eu2+ (RE=La or Y) was determined to be of 0.05. The excitation and emission peaks of all as-synthesized phosphors were wide bands. The excitation bands ranged from 250 to 400 nm, which matched well with the wavelength of near ultraviolet white light-emitting diodes (LED) chip and could be used as a potential candidate for the fabrication of white LED. The emission bands from 450 to 550 nm were typical 5d-4f transition emission of Eu2+ and displayed un-symmetry profiles because of the two substitution sites of Ba2+ with Eu2+. 相似文献
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