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Tunable emission from LiBaBO 3 :Eu 3+ ;Bi 3+ phosphor for solid‐state lighting
Author(s) -
Lephoto Mantwa Annah,
Tshabalala Kamohelo George,
Motloung Selepe Joel,
Shaat Samy Khalil Kamel,
Ntwaeaborwa Odireleng Martin
Publication year - 2017
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.3295
Subject(s) - phosphor , europium , photoluminescence , analytical chemistry (journal) , monoclinic crystal system , materials science , scanning electron microscope , luminescence , impurity , doping , powder diffraction , bismuth , chemistry , crystal structure , crystallography , optoelectronics , organic chemistry , chromatography , composite material , metallurgy
Europium (Eu 3+ ) and bismuth (Bi 3+ ) co‐activated LiBaBO 3 powder 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 LiBaBO 3 phosphors 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 LiBaBO 3 host was estimated to be 3.33 eV from the U V / v is absorption data. Blue emission was observed from the LiBaBO 3 host, 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 Eu 2+ and Eu 3+ , respectively. Furthermore, after codoping with Bi 3+ , the emission intensity of Eu 3+ located at 613 nm was significantly enhanced. From the Commission Internationale de I′Eclairage (CIE) color coordinates, white emission was observed from LiBa 1– x BO 3 : x Eu 3+ ( 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.