Jaeyoung Hwang

Synthesis and characterization of a new π -conjugated polymer with cyanoacrylate side chain for organic thin film transistors

AbstractA new copolymer, poly(carbazol-9-yl)phenyl)-2-cyanoacrylate)-alt-(2,2′-(1,5-bis(hexyloxy)naph thalene-2,6-diyl)dithiophene)) (PCCNT) with cyanoacrylate, was synthesized by the Stille coupling reaction for p-type semiconductors in OTFTs. FTIR and 1H NMR spectroscopes confirmed the structure of PCCNT. The molecular weight of polymer was 14.6 kDa with polydispersity index of 1.72 using GPC. The obtained polymer with long alkyl side chains demonstrated good solubility. PCCNT has good thermal stability of (Td=324) as well as good oxidation stability with a HOMO level of −5.35 eV. UV-Vis absorption maximum of the polymer was found at 431 nm in solution and at 444 nm for the film, respectively. In the photoluminescence (PL), the large red-shift was observed from solution emission (λmax 493 nm) to film emission (λmax 539 nm) due to an intermolecular interaction. The fabricated bottom gate-top contact organic thin film transistors (OTFTs) showed field-effect mobility of 9.02×10−5 cm2/Vs and threshold voltage of −3 V.

Synthesis of donor-acceptor alternating copolymer by uncatalyzed condensation polymerization

Abstract

Synthesis and characterization of perfluorinated phenyl-substituted Ir(III) complex for pure green emission

A new deep green-emitting material, a 3,5-bis(trifluoromethyl)phenylene-substituted iridium(III) complex, fac-tris[2-(3′,5′-bis(trifluoromethyl)biphenyl-3-yl)pyridine]iridium (Ir(mtfppy)3), was synthesized. Introducing bulky 3,5-bis(trifluoromethyl)phenylene to the metaposition of pyridyl-phenyl results in blue-shifted narrow emission compared to that of Ir(ppy)3. The organic light-emitting diode (OLED) based on Ir(mtfppy)3 shows a maximum external quantum efficiency (EQE) of 23.2% with the CIE coordinates of (0.26, 0.63) without strong microcavity effect.

New Blue Emitting Material with Asymmetric Limb Structure.

The new assymmetric limb-structured blue light emitting material, composed of anthracene main core, naphthalene units at 9, 10-position of anthracene and xylene units at 2,3-positon of anthracene, was designed and synthesized. The three-dimensional structure from theoretical calculation was characterized to elucidate non-copolar structure with inhibited intermolecular interaction. The limb-structured blue material was thermally stable up to 373 degrees C with T(g) of 143 degrees C. ITO/TAPC/CBP (3% BMPNA)/Bphen/LiF/Al device exhibits the maximum quantum efficiency of 3.42% and maximum current efficiency of 3.07 cd/A with deep blue emission of (0.141, 0.115) CIE coordinates.

Synthesis and Characterization of Poly(silole-pyridine)

New poly(silole-pyridine) was designed and synthesized. Polymer was obtained by Yamamoto coupling reaction. The structure of obtained polymer was characterized by the spectroscopic methods such as FT-IR and 1H-NMR. The resulting polymer was soluble in common organic solvents such as toluene, tetrahydrofurane, chloroform, chlorobenzene, etc. The obtained polymer showed good thermal stabilities, which was characterized by TGA and DSC.

Synthesis and Characterization of Violet Light Emitting Polymer based on Fluorene and Dimethylsilane

New fluorene based light emitting polymer, poly[(4-(9,9-didecyl-9H-fluoren-2-yl) phenyl)dimethyl(phenyl)silane] (PFDPS), was synthesized by palladium-catalzed Suzuki coupling reaction. The obtained copolymer was characterized by 1H-NMR, and IR-spectroscopy. The polymer showed good solubility in common organic solvents and weight average molecular weight of 16,300 with polydispersity index of 1.4. The maximum photoluminescence of the solution and film of the polymer was observed at 392 nm and 410 nm, respectively. The double-layered device with the configuration, ITO/PEDOT/PFDPS/LiF/Al structure has a turn-on voltage at about 5.5 V and maximum brightness of 9.40 cd/m2, and emitted violet light at 414 nm.

Research for Pyrolysis of Metal Caps

Abstract The application of metal caps has been continuously increased as real life are extended. Metal caps is usually made of aluminum and polyethylene(PE) as packing. Since metal caps contain 75% aluminum on a weight basis, metal caps may be a valuable source when these were properly recovered.The recovery methods of metal caps have mechanical peeling and incineration. However these are either hard to apply in some case or environmentally unacceptable. So in this investigation, recovery method of aluminum from metal caps was investigated using pyrolysis. The result shows that pyrolysis temperature and pyrolysis time was 450 ℃ and 120min. respectively. Also 100% of aluminum was recovered from metal caps. Heat content of recovered oil was high enough to use as a fuel representing 7,425.0, 7,793.1, 7,583.2, 7,726.2(cal/g). Heavy metal contens in the oil were under regulatory limit indicating.Key Words :Pyrolysis, Alumminum, Metal cap 1) 1. 서 론 현재 우리나라에서는 기간산업의 발달과 그 기기들의 사용이 보편화되고 생활수준의 향상으로 알루미늄의 수요는 매년 증가되고 있다. 이에 따른 알루미늄의 국내 생산량은 매년 증가하고 있으나 급격히 늘어나는 수요량을 충족하지 못하여 생상량의 대부분을 수입에 의존하고 있는 실정이다(비철금속회보, 1993). 그리고 국내의 알루미늄의 수요는 대부분 건축자재와