Praseodymium-Doped Sialon Red Phosphors Prepared By Polymer-Derived Method

The red emission praseodymium (Pr)-doped silicon based oxynitride phosphors were prepared by a novel polymer-derived synthesis route via nitridizing and calcining precursor formed by reacting polycarbosilane with Pr acetylacetonate (SiON:Pr) or Pr and Al acetylaeetonates (SiAlON:Pr). The effects of sintering temperatures and nominal ratios of Si/Pr or (Si+Al)/Pr on photoluminescence properties were examined. It was shown that the alpha-Si3N4 and beta-Si3N4 phases coexisted, and two emission peaks at 566 um and 610 nm were observed for the SiON:Pr phosphor. The mixed beta-SiAlON and Si2N2O phases were identified for the SiAlON:Pr phosphor sintered at 1550 degrees C, with two emission peaks at 566 nm and 610 um. However, when sintered at 1600 degrees C and 1650 degrees C, the SiAlON:Pr phosphors exhibited only one emission peak at 623 nm with a predominant beta-SiAlON phase. The double-exponential photoluminescence behaviors with the decay time of 30-45 mu s were found for the SiAlON:Pr phosphors, which corresponded to the transitions of D-1(2)-> H-3(4).