<link rel="stylesheet" href="styles.cf390c6bfbe7555f.css">

學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Author: search.filters.author.Whang, WTSubject: search.filters.subject.electroluminescence

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item type:Item,
    A study of the relationship between the electroluminescence characteristics and compositions of PPV-PVA-based polymers
    (1996-08-01)
    Chang, WP
    ;
    Whang, WT
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    A series of poly(p-phenylene vinylene) (PPV)-poly(vinyl alcohol) (PVA)-based polymers were prepared from the PPV precursor and PVA aqueous solution mixtures. The luminescence characteristics of the PPV-PVA-based polymers were dependent on their composition and the following treating conditions. The emitted light of the PPV-PVA-based light-emitting diodes (LEDs) shifted from yellow-green (550 nm) to blue (485 nm) as the PVA component increased. The infra-red (i.r.) absorption spectra showed that some part of the PPV precursor could react with PVA to form C-O-C linkages and interrupted the conjugation of PPV polymer chains. This resulted in decrease of the conjugated chain length, as evidenced in ultraviolet-visible u.v.-vis. absorption spectra. The relative photoluminescence (PL) intensity increases with decreasing the conjugated chain length. The relative electroluminescence (EL) decreases with the increase of the PVA component in the polymers. However, both PL and EL intensity normalized with PPV molar ratio of PPV-PVA-based polymers were higher than that of pure PPV. The relative low threshold voltage at 4-6 V was found in these PPV-PVA-based polymer LEDs with Al (negative) and indium-tin oxide ITO (positive) as the two electrodes. Copyright (C) 1996 Elsevier Science Ltd.
  • Thumbnail Image
    Item type:Item,
    Significant improvement on the electroluminescence characteristics of MEH-PPV by blending with PMMA
    (2000-09-01)
    Chao, CS
    ;
    Whang, WT
    ;
    Chuang, KR
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    A significant improvement on the electroluminescence threshold voltage from 5.5 volts down to 2.9 volts of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) in the Ca/polymer/ITO diode is observed by incorporating a non-conjugated PMMA into MEH-PPV. The threshold voltage of the material decreases with the poly(methyl methacrylate) (PMMA) content. Near-field scanning absorption and photoluminescence micrographs show that the PMMA domains dispersed in the continuous MEH-PPV phase appear to be similar to sesame seeds embedded in the MEH-PPV pancakes. The resistivity of PMMA is two orders lower than that of MEH-PPV. The excellent electrical conduction of PMMA in Ca/PMMA/ITO glass devices is not due to a pin-hole defect mechanism but may result from the electron hopping from Ca through the carbonyl groups in the PMMA. The significant improvement in the threshold Voltage may be due to the combination of the electron hopping in the thin PMMA sesame seeds and the thinner thickness effect of MEH-PPV in the light emitting layer.
  • Thumbnail Image
    Item type:Item,
    Characteristics of an electropolymerized PPV and its light-emitting diode
    (1996-04-01)
    Chang, WP
    ;
    Whang, WT
    ;
    Lin, PW
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    Poly(phenylene vinylene) (PPV) has been prepared successfully from p-xylylenebis(triphenylphosphonium bromide) in acetonitrile solution via an electroreduction polymerization. p-Xylylenebis(triphenylphosphonium bromide) also acted as an electrolyte in the solution. The resultant electropolymerized PPV film was transparent and dense, and had considerable adhesion to an indium-tin oxide (ITO) electrode. The electropolymerized PPV showed a blue shift both in the ultraviolet-visible absorption spectrum and photoluminescence, compared with the PPV prepared from a p-xylylenebis(tetrahydrothiophenium chloride) precursor route, indicating that it has a shorter pi-conjugated chain length. The infra-red absorption spectra showed a stable P-C bond on the electropolymerized PPV chain. The Al/electropolymerized PPV/ITO light-emitting diode emitted green light with an emission maximum at 530 nm. Annealing the electroluminescence device in a high vacuum oven at 160 degrees C for 3 h significantly enhanced the electroluminescence performance as a result of improvement of the interfacial contact between PPV and the Al metal electrode. Copyright (C) 1996 Elsevier Science Ltd.
  • Thumbnail Image
    Item type:Item,
    A study of the relationship between the electroluminescence characteristics and compositions of PPV-PVA-based polymers
    (1996-08-01)
    Chang, WP
    ;
    Whang, WT
    ;
    材料科學與工程學系
    ;
    Department of Materials Science and Engineering
    A series of poly(p-phenylene vinylene) (PPV)-poly(vinyl alcohol) (PVA)-based polymers were prepared from the PPV precursor and PVA aqueous solution mixtures. The luminescence characteristics of the PPV-PVA-based polymers were dependent on their composition and the following treating conditions. The emitted light of the PPV-PVA-based light-emitting diodes (LEDs) shifted from yellow-green (550 nm) to blue (485 nm) as the PVA component increased. The infra-red (i.r.) absorption spectra showed that some part of the PPV precursor could react with PVA to form C-O-C linkages and interrupted the conjugation of PPV polymer chains. This resulted in decrease of the conjugated chain length, as evidenced in ultraviolet-visible u.v.-vis. absorption spectra. The relative photoluminescence (PL) intensity increases with decreasing the conjugated chain length. The relative electroluminescence (EL) decreases with the increase of the PVA component in the polymers. However, both PL and EL intensity normalized with PPV molar ratio of PPV-PVA-based polymers were higher than that of pure PPV. The relative low threshold voltage at 4-6 V was found in these PPV-PVA-based polymer LEDs with Al (negative) and indium-tin oxide ITO (positive) as the two electrodes. Copyright (C) 1996 Elsevier Science Ltd.