title: Tunable emission from LiBaBO3:Eu3+;Bi3+phosphor for solid-state lighting.
abstract: Europium (Eu3+) and bismuth (Bi3+) co-activated LiBaBO3powder phosphors were synthesized by a solid-state reaction and the structure, particle morphology, optical and photoluminescent properties were investigated. X-Ray diffraction patterns of the LiBaBO3phosphors crystallized in a pure monoclinic phase, i.e. there were no secondary phases due to either incidental impurities or undecomposed starting materials. Scanning electron microscopy images showed that the powders were made up of fluffy needle-like particles that were randomly aligned. The band-gap of the LiBaBO3host was estimated to be 3.33 eV from the UV/vis absorption data. Blue emission was observed from the LiBaBO3host, which is ascribed to self-activation of the host matrix. In addition, greenish-blue (493 nm) and red (613 nm) emissions were observed from europium-doped samples and were attributed to the emissions of Eu2+and Eu3+, respectively. Furthermore, after codoping with Bi3+, the emission intensity of Eu3+located at 613 nm was significantly enhanced. From the Commission Internationale de I'Eclairage (CIE) color coordinates, white emission was observed from LiBa1-xBO3:xEu3+(x = 0.020 and 0.025) phosphor powders with color coordinates of x = 0.368, y = 0.378 and x = 0.376, y = 0.366, respectively.
authors.affiliation: Department of Physics, University of the Free State, Phuthaditjhaba, South Africa.
authors.forename: Mantwa Annah
authors.initials: MA
authors.lastname: Lephoto
authors.affiliation: Department of Physics, University of the Free State, Phuthaditjhaba, South Africa.
authors.forename: Kamohelo George
authors.initials: KG
authors.lastname: Tshabalala
authors.affiliation: Department of Physics, University of the Free State, Phuthaditjhaba, South Africa.
authors.forename: Selepe Joel
authors.initials: SJ
authors.lastname: Motloung
authors.affiliation: Department of Physics, Islamic University, Gaza, Palestine.
authors.forename: Samy Khalil Kamel
authors.initials: SKK
authors.lastname: Shaat
authors.affiliation: School of Physics, University of the Witwatersrand, Wits, South Africa.
authors.forename: Odireleng Martin
authors.identifier: http://orcid.org/0000-0002-7259-0594
authors.initials: OM
authors.lastname: Ntwaeaborwa
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D049408:Luminescent Agents; D005063:Europium; D001729:Bismuth
keywords: energy transfer; phosphor; photoluminescence; solid-state lighting