title: Synthesis of the phase pure Ba3Si6O12N2:Eu2+ green phosphor and its application in high color rendition white LEDs.
abstract: The promising green oxynitride phosphor, Ba3Si6O12N2:Eu(2+), was synthesized at 1350 °C for 5 hours under a reducing N2/H2 (5%) atmosphere by using the solid-state reaction method. The phase purity was investigated by varying the nominal compositions, and the pure phase was achieved by carefully controlling the Si/Ba and O/Ba ratios. The phosphor displayed a broad excitation band spanning from the ultraviolet (UV) to the blue spectral region, and showed a single symmetrical emission band peaking at 525 nm with a full width at half maximum (FWHM) of ∼ 68 nm. The as-prepared green phosphor exhibited a small thermal quenching, which remained 90% of the initial emission intensity when measured at 200 °C. The internal and external quantum efficiencies measured under 450 nm excitation were 68 and 38%, respectively. Color temperature-tunable white LEDs with a high color rendering index of Ra = 88-94 were attained by combining the prepared green phosphor and a red phosphor Sr2Si5N8:Eu(2+) with a blue LED chip.
authors.affiliation: Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China. Xie.Rong-Jun@nims.go.jp.
authors.forename: Wanyuan
authors.initials: W
authors.lastname: Li
authors.forename: Rong-Jun
authors.initials: RJ
authors.lastname: Xie
authors.forename: Tianliang
authors.initials: T
authors.lastname: Zhou
authors.forename: Lihong
authors.initials: L
authors.lastname: Liu
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Zhu