Pr[super]3+-doped Li sub(2SrSiO) sub(4) red phosphor for white LEDs

Novel red phosphors, Li sub(2Sr) sub(1)-1.5xSiO sub(4:xPr[super]3+ (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 [super]3H) sub(4)-->[super]3P sub(2, [super]3H) sub(4)-->[super]3P sub(1+[super]1I) sub(6), [super]3H sub(4-->[super]3P) sub(0) of Pr[super]3+ ion. The red emissions at 606 and 610 nm were originated from the [super]3P sub(0-[super]3H) sub(6) and [super]1D sub(2-[super]3H) sub(4) transitions of Pr[super]3+. The optimum doping concentration of Pr[super]3+ in Li sub(2Sr) sub(1)-1.5xSiO sub(4:xPr[super]3+ was determined to be x=0.004. With the concentration of Pr[super]3+ over x=0.004, the fluorescence intensity of Li) sub(2)Sr sub(1-1.5xSiO) sub(4):xPr[super]3+ decreased, indicating the concentration quenching occurred.