• 제목/요약/키워드: optoelectronic materials

검색결과 283건 처리시간 0.026초

Synthesis and Optical Properties of Poly(hydroxyphenylbenzoxazole): A Colorimetric and Fluorescent Sensor for Ionic Species

  • Lee, Jin-Koo;Kim, Tae-Hyun;Kim, Young-shin;Gang Li;Park, Won-Ho;Lee, Taek-Seung
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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    • pp.23-24
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    • 2003
  • We synthesized a poly[2-(2'-hydroxyphenyl) benzoxazole] under the two step procedures of Suzuki coupling polymerization with corresponding monomers followed by the deprotection of benzyl group. The polymer in DMF solution is applicable to colorimetric sensing fluoride anion, which shows a color change from colorless to yellow. High sensitivity to fluoride anion compared to other anions such as phosphate, chloride, and sulfate is ascribed to the high coordination ability of the 2-(2'-hydroxy phenyl)benzoxazole moiety in the polymer chain. Emission shift by metal cations, which can be applied to fluorescent sensing w as also observed in the polymer solution.

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Chromogenic and Fluorogenic Polymer Systems for Optical Sensing and Patterning

  • Lee, Taek-Seung;Kim, Tae-Hyeon;Kim, Tae-Hoon;Choi, Moon-Soo;Kim, Hyung-Jun;Kwak, Chan-Gyu;Lee, Jung-Hyo;Lee, Chi-Han
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.175-175
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    • 2006
  • Considering the number of chemosensors that have been developed for the sensing of metal ions, only a few chemosensors for fluoride anion have been described in the literature that are based on fluorescent or chromogenic responses. We performed colorimetric anion sensing based on the binding of anion analytes with hydrogen donor group in polymer backbone resulting in naked-eye color change and fluorescent quenching. Our challenges using hydrogen donor moiety was designed effectively are continuing in order for high selectivity and sensitivity for ultimate applications such as fluid solution sensing in biomolecules and gas vapor sensing.

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Self-Consistent Subband Calculations of AlGaN/GaN Single Heterojunctions

  • Lee, Kyu-Seok;Yoon, Doo-Hyeb;Bae, Sung-Bum;Park, Mi-Ran;Kim, Gil-Ho
    • ETRI Journal
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    • 제24권4호
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    • pp.270-279
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    • 2002
  • We present a self-consistent numerical method for calculating the conduction-band profile and subband structure of AlGaN/GaN single heterojunctions. The subband calculations take into account the piezoelectric and spontaneous polarization effect and the Hartree and exchange-correlation interaction. We calculate the dependence of electron sheet concentration and subband energies on various structural parameters, such as the width and Al mole fraction of AlGaN, the density of donor impurities in AlGaN, and the density of acceptor impurities in GaN, as well as the electron temperature. The electron sheet concentration was sensitively dependent on the Al mole fraction and width of the AlGaN layer and the doping density of donor impurities in the AlGaN. The calculated results of electron sheet concentration as a function of the Al mole fraction are in excellent agreement with some experimental data available in the literature.

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광전자용 재료 연구의 최근현황 (Recent progress in research of optoelectronic materials)

  • Dae-Ho Yoon;Tsuguo Fukuda
    • 한국결정성장학회지
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    • 제4권1호
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    • pp.1-10
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    • 1994
  • It is well known that crystal growth is an essential area of research for optoelectronic materials. In the present paper the growth techniques and the advanced progress in development of crystal materials important for optoelectronic applications are described. New growth techniques, developed in the authors' laboratory, enabling the introduction of expanded applications of new materials are presented. After a review of recent developments of new techniques for optoelectronic materials, own experimental studies will be discussed.

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