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Luminescent Properties of (Ca 1− x Sr x ) 3 SiO 4 (Cl 1− y F y ) 2 :Eu 2+ Phosphors and Their Application for White LED
Author(s) -
Wang Jing,
Liu Zongmiao,
Ding Weijia,
Su Qiang
Publication year - 2009
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2009.02382.x
Subject(s) - phosphor , materials science , photoluminescence , analytical chemistry (journal) , luminescence , emission spectrum , spectroscopy , light emitting diode , spectral line , optoelectronics , chemistry , physics , chromatography , quantum mechanics , astronomy
A series of intense green/orange (Ca 1− x Sr x ) 3 SiO 4 Cl 2 :Eu 2+ and Ca 3 SiO 4 Cl 2−2 y F 2 y :Eu 2+ phosphors were synthesized by a high‐temperature (HT) solid‐state reaction and were characterized by means of X‐ray powder diffraction spectroscopy, photoluminescence excitation, and emission spectra. Both of the phosphors Ca 3 SiO 4 Cl 2 :Eu 2+ with a low temperature (LT)/HT phase show intense broad absorption bands between 250 and 450 nm, matching well with the near‐ultraviolet (n‐UV) (380–420 nm) emission band of InGaN‐based chips, and exhibit a green emission (510 nm) and a tunable yellow (551 nm) to orange emission (577 nm), ascribed to the allowed 5 d →4 f transition of Eu 2+ ion in LT‐ and HT phases, respectively. The green emission can be greatly enhanced by substitution of Ca 2+ by Sr 2+ and Cl − by F − . The emission intensity of Eu 2+ is about 160% ( x =0.01, y =0) and 270% ( x =0, y =0.03) times as strong as that of Ca 3 SiO 4 Cl 2 :Eu 2+ . By combining with n‐UV (∼398 nm) InGaN chips, intense white light emitting diodes (LEDs) were made based on a blend of blue chlorophosphate phosphor, green Ca 3 SiO 4 Cl 2 :Eu 2+ with a LT phase, and orange Ca 3 SiO 4 Cl 2 :Eu 2+ with a HT phase. Tunable warm white (2648–4057 K) LEDs with a high color‐rendering index (86–94) were successfully fabricated.