Browsing by Author "Yao, YH"

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Polarized white emission from fluorene-based polymer blends
(2005-10-01)
Yao, YH
;
Kung, LR
;
Hsu, CS
;
應用化學系
;
Department of Applied Chemistry
Three alternating co-polyfluorenes emitting primary red, green and blue (RGB) colors have been synthesized via a palladium-catalyzed Suzuki coupling reaction. All copolymers reveal good thermal stability and nematic liquid crystalline behavior. The polymers were fabricated to form a polarized electroluminescent device using poly(ethylene dioxythiophene)-poly(styrene sulfonicacid) (PEDOT-PSS) as an alignment layer. For the case of primary colors, a host-guest approach that utilized a blue light emission P1 as a host with a green light P2 or a red light P3 as a guest led to approximately two- to fourfold enhancement in luminescence in comparison with that of a neat film in polymer light emitting diodes (PLEDs), 1039 versus 2205cd/m(2) and 284 versus 1146cd/m(2). In the case of white light, as a consequence of blending, polarized emission peak ratio of up to 4.4 and a pure white luminance brightness of up to 1895cd/m(2) have been attained.
Synthesis of UV-curable liquid crystalline diacrylates for the application of polarized electroluminescence
(2006-01-01)
Yao, YH
;
Kung, LR
;
Chang, SW
;
Hsu, CS
;
應用化學系
Two series of UV-curable rod-like diacrylates containing bis-tolane (M1 - M5) and bis-stilbene (M6 - M10) mesogens were synthesized. All of the diacrylates were prepared through convergent syntheses involving palladium-catalysed coupling reactions. The thermal transitions and mesomorphic properties of the diacrylates were characterized by differential scanning calorimetry and optical microscopy. All the bis-tolane-based monomers reveal nematic phases, except M5 which shows no mesomorphic behaviour. For the bis-stilbene based monomers, most show no mesomorphic behavior and only M7 and M9 exhibit a SmA phase.