title: A novel synthetic method of Sr2Si5N8:Eu2+ from SrSi2O2N2:Eu2+ by carbo-thermal reduction and nitridation.
abstract: We demonstrated a novel synthetic route from Eu(2+)-doped oxy-nitride phosphors to prepare Eu(2+)-doped nitride phosphors. The Eu(2+)-doped Sr2Si5N8 phosphor was prepared by carbo-thermal reduction and nitridation from Eu(2+)-doped SrSi2O2N2 mixed with carbon. Eu(2+)-doped SrSi2O2N2 phosphor was prepared at 1350-1500 degrees C, and subsequently Eu(2+)-doped Sr2Si5N8 phosphor was synthesized at 1550-1700 degrees C. When over 4 wt% of carbon was added, the phase of SrSi2O2N2:Eu2+ changed to the one of Sr2Si5N8:Eu2+. The data of photoluminescent spectra and X-ray powder diffraction (XRD) patterns proved the phase transition. The product showed a red emission of 616 nm at the blue excitation of 450 nm. The shape of phosphor changed from a plate type to a rod one. We also prepared some red phosphors of SrSi(x)O(o)N(n):Eu2+ according to the different ratio of Si. Although the Si content was different from each other, there was no change in XRD patterns.
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology, Daejeon 305-543, Korea.
authors.forename: Kang Sik
authors.initials: KS
authors.lastname: Choi
authors.forename: Soon Duk
authors.initials: SD
authors.lastname: Jee
authors.forename: Jung Pyo
authors.initials: JP
authors.lastname: Lee
authors.forename: Chang Hae
authors.initials: CH
authors.lastname: Kim