• 제목/요약/키워드: chemical materials

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Progress In Commercialization Of Light Emitting Polymers: Dow Polyfluorenes

  • Wu, W.;Inbasekaran, M.;Hudack, M.;Welsh, D.;Yu, W.;Chen, Y.;Wang, C.;Kram, S.;Tacey, M.;Bernius, M.;Fletcher, R.;Kiszka, K.;Munger, S.;O'Brien, J.;Hills, M.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.340-343
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    • 2002

  • We report here our recent progress in the development and commercialization of polyfluorenes emitting red, green and blue (ROB) colors as materials for light emitting diodes (LEDs). Our patented version of the Suzuki coupling process has been used to synthesize a variety of fluorenebased homopolymers and copolymers emitting colors across the entire visible spectrum. The optical and electronic properties of the polymers are tailored through selective incorporation of different aromatic units into the polyfluorene backbone. Our latest green emitter, reported herein, provides very efficient devices with a low turn-on voltage of 2.25 V, a peak efficiency of 10.5 Cd/A at 6,600 Cd/$m^2$ at 4.85 V. These devices maintain an efficiency of greater than 10 Cd/A up to 50,000 Cd/$m^2$ and demonstrate very good stability as exemplified by a device half-life of greater than 1,500 hours starting from 1,100 Cd/$m^2$. Considerable progress has also been made with red and blue emitters and will be the subject of this presentation.

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Isolation and Synthesis of Tryptamine Derivatives from a Symbiotic Bacterium Xenorhabdus nematophilus PC

  • Paik, Seung-Uk;Park, Myung-Kwang;Jhun, Seong-Hoon;Park, Heai-Ku;Lee, Chun-Soo;Cho, Bum-Rae;Byun, Hong-Sik;Choe, Seok-Burm;Suh, Seong-Il
    • Bulletin of the Korean Chemical Society
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    • 제24권5호
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    • pp.623-626
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    • 2003

  • Nematophin and its analog incorporating tryptamine unit have been isolated and characterized from strain XRPC of a symbiotic bacterium Xenorhabdus nematophilus, which was newly isolated from Korean entomopathogenic nematodes. The stereoselective synthesis of these compounds was accomplished, and the relative configurations were determined. Nematophin exhibited potent antibacterial activities over several strains of methicillin-resistant S. aureus (MRSA) comparable to those of vancomycin.

  • https://doi.org/10.5012/bkcs.2003.24.5.623 인용 PDF KSCI

MOCVD of GaN Films on Si Substrates Using a New Single Precursor

  • Song, Seon-Mi;Lee, Sun-Sook;Yu, Seung-Ho;Chung, Taek-Mo;Kim, Chang-Gyoun;Lee, Soon-Bo;Kim, Yun-Soo
    • Bulletin of the Korean Chemical Society
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    • 제24권7호
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    • pp.953-956
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    • 2003

  • Hexagonal GaN (h-GaN) films have been grown on Si(111) substrates by metal organic chemical vapor deposition using the azidodiethylgallium methylamine adduct, Et₂Ga(N₃)·NH₂Me, as a new single precursor. Deposition was carried out in the substrate temperature range 385-650 °C. The GaN films obtained were stoichiometric and did not contain any appreciable amounts of carbon impurities. It was also found that the GaN films deposited on Si(111) had the [0001] preferred orientation. The photoluminescence spectrum of a GaN film showed a band edge emission peak characteristic of h-GaN at 378 nm.

  • https://doi.org/10.5012/bkcs.2003.24.7.953 인용 PDF KSCI