Browsing by Author "Hsu, Shou-Chian"

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A simple chemical method for the preparation of silver nanocables from self-assembling tubular Ag+ precursors
(2006)
Weichold, Oliver
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Hsu, Shou-Chian
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Moeller, Martin
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材料科學與工程學系
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Department of Materials Science and Engineering
A simple and efficient method for the in situ fabrication at ambient temperature of nanocables consisting of a silver core and an insulating organic shell from a self-assembling silver precursor is presented. The precursor assembles into tubular aggregates several microns in length, which template the formation of silver wires, under defined reaction conditions. Proper control of the reaction conditions, such as reagent concentrations and the method of reduction, is important in order to obtain well-defined nanocables as individual dispersed entities. These consist of 30 - 45 nm silver cores, 60 - 70 nm walls, and an aspect ratio of >200. IR spectroscopy revealed the organic sheath to be cross-linked via a bridging-type coordination to the silver ions, which helps in the formation of the tubular aggregation and provides structural rigidity.
Electroluminescence and electron transport characteristics of aromatic polyimides containing 1,3,4-oxadiazole moiety
(2007-06-13)
Hsu, Shou-Chian
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Whang, Wha-Tzong
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Chao, Ching-Shiun
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材料科學與工程學系
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Department of Materials Science and Engineering
Single and double layer polymer light-emitting diodes (LEDs) were fabricated by using 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole (BAO)-based aromatic polyimides (APIs). All the resultant APIs have high glass transition temperatures (T-g>250 degrees C) and high thermal decomposition temperatures (T-d>510 degrees C). The APIs exhibit broad fluorescent characteristic, and the fluorescent intensity is related to the intermolecular chain's orientation. BAO-3,3 '-oxydiphthalic anhydride (ODPA) and BAO-4,4 '-(hexafluoro-iso-propylidene) diphthalic anhydride show electroluminescent property in single layer LED devices. By inserting BAO-ODPA in the poly(p-phenylene vinylene)-poly(vinylalcohol) LED device to form a double layer device, the EL efficiency can be improved by two orders of magnitude. (C) 2007 Elsevier B.V. All rights reserved.
Large-scale fabrication of ZnO nanocrystals by a simple two-step evaporation-oxidation approach
(2007-04-01)
Hsu, Shou-Chian
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Whang, Wha-Tzong
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Hung, Chin-Hsien
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材料科學與工程學系
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Department of Materials Science and Engineering
Single crystal structures of ZnO nanocrystals were prepared on quartz and polyimide (PI) film substrates by using a thermal coater to promote thermal evaporation, followed by air circulation at 350 degrees C for 2 h to effect oxidation. HRTEM and TEM images show the individual ZnO nanocrystals have regular lattice order without stacking faults. After dispersion by an ultrasonic bath, ZnO deposited on PI film substrates can consist of individual and well-distributed nanocrystals with an average crystal size of 2030 nm. In photoluminescence, the nanocrystalline ZnO exhibits strong UV emission at 395 nm, with no emission in the visible spectrum. The synthetic method described in this paper provides a simple and efficient method to fabricate ZnO nanocrystals on a large scale. (c) 2006 Elsevier Inc. All rights reserved.