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Structure and Photoluminescence of A Blue‐Green‐Emitting Phosphor for Near‐ UV White LED s
Author(s) -
Ling Hongya,
Huang Jinping,
Hou Binghu,
Liu Jie,
Yu Xibin
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12917
Subject(s) - phosphor , luminescence , boric acid , photoluminescence , light emitting diode , analytical chemistry (journal) , crystal structure , materials science , fluorescence , ultraviolet , chemistry , optoelectronics , crystallography , optics , physics , organic chemistry , chromatography
A series of phosphors Ca 12(0.97− x ) Al 14 O 32 F 2 : 0.03 Ce 3+ , x Tb 3+ have been prepared by a hightemperature solid‐state reaction using boric acid as flux. These oxyfluorides crystallize in cubic structure, I 4 ¯ 3 d space group. Under the near ultraviolet excitation within wavelength range 310–390 nm, Ca 12(0.97− x ) Al 14 O 32 F 2 : 0.03 Ce 3+ , x Tb 3+ phosphors exhibit an intense emission covering a broad band of 370–500 nm derived from the 5 d →4 f transitions of Ce 3+ and a characteristic emission at 544 nm of Tb 3+ . The emission can be tuned from blue to green by altering the relative ratio of Ce 3+ to Tb 3+ in the composition. The energy‐transfer mechanism from Ce 3+ to Tb 3+ is investigated based on the site occupancy of the luminescence center in the crystal structure of the Ca 12 Al 14 O 32 F 2 host. More importantly, when a certain amount of boric acid is added as flux in the synthesis, the fluorescence intensity of the phosphors increases about 65%. Because of its broad excitation and efficiently tunable blue to green luminescence, the Ca 12(0.97− x ) Al 14 O 32 F 2 : 0.03 Ce 3+ , x Tb 3+ phosphors may find promising application as a near UV‐convertible phosphor for white‐light‐emitting diodes.