Browsing by Author "Chen, Chin-Hsin"

Now showing 1 - 3 of 3

Characterizations of UV-Curable Montmorillonite/Epoxy Nanocomposites Prepared by a Hybrid of Chemical Dispersion and Planetary Mechanical Milling Process
(2012-03-15)
Huang, Heh-Chang
;
Huang, Shu-Ping
;
Hsieh, Tsung-Eong
;
Chen, Chin-Hsin
;
材料科學與工程學系
Ammonium salt, [2-(methacyloyloxy)ethyl] trimethylammonium methyl sulfate (MAOTMA), was adopted to modify montmorillonite (MMT) via the cationic exchange process in an acidic environment and a successful enlargement of MMT lamellar spacing from 1.18 to 1.39 nm was identified by x-ray diffraction and Fourier-transform infrared spectroscopy. Accordingly, UV-curable epoxy nanocomposite resins containing various amounts of MAOTMA-modified MMT were prepared with the aid of a planetary mechanical milling process. Transmission electron microscopy revealed a uniform dispersion of exfoliated MMT lamella in epoxy matrix, leading to the distinct improvements on thermal stability and thermal expansion property of nanocomposite samples. Calcium (Ca) test indicated that the good dispersion of MMT fillers in polymer effectively suppresses the moisture permeation in sample matrix. More than twofold increment on retention time of 5% Ca hydrolysis and 20% improvement on the permeation kinetic parameters were observed in the nanocomposite sample containing 8 wt % MMT in comparison with the pristine epoxy sample. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3199-3207, 2012
Direct encapsulation of organic light-emitting devices (OLEDs) using photo-curable co-polyacrylate/silica nanocomposite resin
(2007-08-01)
Wang, Yu-Young
;
Hsieh, Tsung-Eong
;
Chen, I-Ching
;
Chen, Chin-Hsin
;
材料科學與工程學系
Direct encapsulation of organic light-emitting devices (OLEDs) was realized by using highly transparent, photo-curable co-polyacrylate/silica nanocomposite resin. Feasibility of such a resin for OLED encapsulation was evaluated by physical/electrical property analysis of resins and driving voltage/luminance/lifetime measurement of OLEDs. Electrical property analysis revealed a higher electrical insulation of photocured nanocomposite resin film at 3.20 x 1012 9 in comparison with that of oligomer film at 1.18 x 10(12) Omega at 6.15 V to drive the bare OLED. This resulted a lower leakage current and the device driving voltage was efficiently reduced so that the nanocomposite-encapsulated OLED could be driven at a lower driving voltage of 6.09 V rather than 6.77 V for the oligomer-encapsulated OLED at the current density of 20 mA/cm(2). Luminance measurement revealed a less than 1.0% luminance difference of OLEDs encapsulated by various types of resins, which indicates that the photo-polymerization takes very little effect on the light-emitting property of OLEDs. Lifetime measurement of OLEDs found that t(80), the time span for the normalized luminance of device drops to 80%, for nanocomposite-encapsulated OLED is 350.17 h in contrast to 16.83 h for bare OLED and 178.17 h for the oligomer-encapsulated OLED. This demonstrates that nanocomposite resin with optimum properties is feasible to OLED packaging and a compact device structure could be achieved via the method of direct encapsulation.
High color-stability for white organic light emitting devices by using phosphorescent sensitizer fluorescent
(2010)
Juang, Fuh-Shyang
;
Hong, Lin-Ann
;
Hsiao, Chih-Jen
;
Wang, Shun-Hsi
;
Ho, Meng-Huan
High color-stability white OLEDs can be achieved by replacing red fluorescent dopant (DCJTB) with yellow dopant (EY-53) in phosphor-sensitized emitter and optimizing the interlayer (CBP) thickness. Device shows the E.Q.E. of 8.2%, the efficiencies of 21.5 cd/A and 8.1 lm/VV with CIE (0.40, 0.46) at 20 mA/cm(2). The shift of ClExy down to (-0.001,-0.001) at a current density of 20 and 200 mA/cm2.