title: Thermally stable white-emitting single composition Na(Sr,Ba)PO4:Eu2+, Mn2+ phosphor for near-ultraviolet-pumped light-emitting diodes.
abstract: Eu(2+) and Mn(2+) codoped, white-emitting Na(Sr,Ba)PO(4) phosphors are prepared, and their emission properties, especially for thermal stability, are thoroughly investigated. The thermal quenching and Eu(2+)/Mn(2+) energy transfer efficiency are totally different in the ratio of alkaline earth metals in host composition, NaBaPO(4), Na(Sr(0.5)Ba(0.5))PO(4), and NaSrPO(4), respectively. Furthermore, by using near-ultraviolet light-emitting diodes (LEDs) and the corresponding Na(Sr(0.5)Ba(0.5))PO(4):Eu(2+), Mn(2+) phosphor as light converters, we demonstrate a bright and thermally stable white-emitting LED. The resultant LED exhibits a warm white light [~4900 K, CIE coordinates of (0.33, 0.31)] with excellent thermal and hydrolytic stabilities comparable to those of commercially available ones, Y(3)Al(5)O(12):Ce(3+) and BaMg(2)Al(16)O(27):Eu(2+). The proposed composition, with its efficient energy transfer, could enable Eu(2+) and Mn(2+) codoped Na(Sr,Ba)PO(4) to be a promising single component phosphor for cost-effective white-emitting LEDs.
authors.affiliation: Advanced Battery Materials Research Group, Korea Research Institute of Chemical Technology, 141 Gajeongro, Yuseong, Daejeon 305-600, South Korea. shochoi@krict.re.kr
authors.forename: Sungho
authors.initials: S
authors.lastname: Choi
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Yun
authors.forename: Sue Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Ha-Kyun
authors.initials: HK
authors.lastname: Jung