Browsing by Author "Ting, Chu-Chi"

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BaMgAl10O17 : Eu blue phosphors with MgO coating and microwave irradiation
(2008-02-01)
Kuo, Kuan-Ting
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Lee, Shu-Ping
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Chen, San-Yuan
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Cheng, Bing-Ming
;
Lu, Hsiao-Chi
Europium-activated barium magnesium aluminate (BaMgAl10O17:Eu (BAM)) phosphor particles were modified by surface coating with MgO using a polyol method. The photoluminescence (PL) properties of the MgO-coated BAM phosphors showed slightly improved blue-emission intensity compared to the unmodified ones, and reached a stronger peak intensity with 5.25% MgO coating, under vacuum ultraviolet (VUV) 147 nm excitation. Upon microwave irradiation on the MgO-coated BAM phosphors, the PL properties of the MgO-coated phosphors exhibited a much enhanced relative PL ratio, and a maximum relative PL ratio can be achieved when as high as 10.5% MgO was deposited on the phosphor surface. However, for mechanically ground phosphor powder, it was found that although the intensity of the MgO-coated BAM turned stronger with increasing MgO concentration under microwave irradiation, the purity of the resulting luminescence was slightly disrupted by the presence of a new peak near 470 nm, corresponding to BaMg3Al14O25 compound. (C) 2007 Elsevier Ltd. All rights reserved.
Effect of microwave irradiation on surface characteristics and luminescent properties of BaMgAl10O17 : Eu blue phosphor
(2008-02-01)
Kuo, Kuan-Ting
;
Lee, Shu-Ping
;
Chen, San-Yuan
;
Cheng, Bing-Ming
;
Lu, Hsiao-Chi
BaMgAl10O17:Eu (BAM) has been an excellent blue-emitting phosphor due to its outstanding luminescence efficiency and purity for plasma display panels. An attempt of employing microwave irradiation to modify the surface properties including morphology and crystallinity of BAM powder was performed in this work. X-ray powder diffraction (XRD) analysis and scanning electron microscopy (SEM) images show that the blue-emitting phosphors after microwave irradiation treatment exhibit better crystallinity and smoother surface. Furthermore, the vacuum ultraviolet photoluminescence spectra show that the luminescent intensity of BAM phosphors can be effectively enhanced by a factor of six times under microwave irradiation treatment. The enhanced luminescent properties can be closely related to the surface modification and reduced defects of the BAM blue-emitting phosphors. (C) 2007 Elsevier Ltd. All rights reserved.
Study on luminous phosphor with improved luminous efficiency for plasma planar backlight
(2005)
Lin, Chin-Ching
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Lee, Shu-Ping
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Kuo, Kuan-Ting
;
Chen, San-Yuan
;
Hsieh, Hank
Highly luminescent efficiency white-light phosphors have been successfully produced by microwave irradiation treatment. The SEM image and XRD analysis reveal that the surface morphology of the white-light phosphors can be notably modified by microwave irradiation from sheet-like into spherical shapes and exhibit with better crystalline property. The VUV PL spectra show that the microwave irradiation treatment can effectively enhance the luminescent efficiency by a factor of 1.5 times for intensity in comparison with that without microwave treatment. The improvement in all visible emission can he related to the modified surface morphology and increased crystalline properties of the white-light phosphors. These results demonstrate that such a simple approach can provide for the fabrication of highly luminescent efficiency phosphors for the optoelectronic devices.