• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.112-112
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• 2006

Detailed surface characteristics of polymer films have been investigated by atomistic molecular dynamics simulations and NEXAFS spectroscopy experiments. The geometric confinement of the surfaces and the necessity to minimize the surface energy lead to the significant molecular organization and orientation in polymer surfaces, with their properties strongly depending upon the atomistic monomer structures. As compared with polymers, oligomeric electronic materials are much more readily aligned by employing various surface anchoring forces, rendering them highly attractive as polarized-light emitting materials and active semiconducting materials in thin film transistors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.637-637
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• 2013

We develop single-crystal poly(3,4-ethylenedioxythiopene nanowires using liquid-bridge-mediated nanotransfer printing via vapor phase polymerization. This direct printing method can simultaneously enable the synthesis, alignment and patterning of the nanowires from molecular ink solutions. Twoor three-dimensional complex structures of various single-crystal organic nanowires were directly fabricated over a large area using many types of molecular inks. This method is capable of generating several optoelectronic devices. LB-nTM is based on the direct transfer of various materials from a mold to a substrate via a liquid bridge between them. To demonstrate its usefulness, we used LB-nTM to fabricate nanowire field-effect transistors and arrays of 6,13-bis (triisopropyl- silylethynyl) pentacene (TIPS-PEN) nanowire field-effect transistors.

• Macromolecular Research
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• 제16권3호
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• pp.238-246
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• 2008

A new strategy using protection-deprotection chemistry was used to prepare branched polymers using the ATRP method only. Among the several monomers with different protecting groups, vinyl benzyl t-butyloxy carbonate (VBt-BOC) and 4-methyl styrene (4-MeSt) could be polymerized successfully to form backbones using the ATRP method in a controlled fashion. The protected groups in the backbones were converted to alkyl bromides and used as initiating sites for branch formation. The benzyl t-butyloxy carbonate groups in the backbones containing VBt-BOC units were first deprotected to benzyl alcohol by trifluoroacetic acid, then converted to benzyl bromide by reacting them with triphenylphosphine/carbon tetrabromide. The benzyl bromide groups in the backbones containing 4-MeSt units could be generated by bromination of the methyl groups using N-bromosuccinimide/benzoyl peroxide. The structures of the prepared polymers were well-controlled, as evidenced by the controlled molecular weight as well as the narrow and unimodal molecular weight distribution.

• 한국세라믹학회지
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• 제35권9호
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• pp.958-968
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• 1998

Porous silica ceramics were prepared using DCCA(Drying Control Chemical Additives) Such as uncharged polymer(Polyethylene glycol) and protein (Lipase) under H2O/Low-grade TEOS=10 C2H5OH/Low-grade TEOS=1 HC1/Low=grade TEOS=0.01 After Plain which doesn't added DCCA and samples of 11 sorts which varied molecular weight of PEG(Mw=600, 1000, 2000) quantity of Lipase and concentration of wat-er were synthesized gellation time and thermal analysis were investigated. After heat-treated at 600, cry-stal structures analyses of SiO2 polymer and characteristics of pores were investigated. Gellation time was retarded about 2-6 times as compared with plain resulting in addition of DCCA and crystal structures ex-hibited amorphous state. Moreover as increase of water a short gellation time was obtained. The samples added PEG showed increase of specific surface areas up to 20-40% and had micropores while those of Lipase were decreased about 90% and showed broad pore size distribution.

• Journal of Korean Vacuum Science & Technology
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• 제4권1호
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• pp.1-5
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• 2000

The C 1s photoelectron energy loss spectra of tris (8-hydroxy-quinoline) aluminum (Alq$_3$) and N,N'-diphenyl-N,N'-bis (3-methyl phenyl)-1,1'-bi-phenyl-4,4'-diamine (TPD) thin films have been investigated. Two major loss structures, namely the plasmon dominated loss lines and shake-up satellites, have been observed. The shake-up spectrum of the C 1s photoelectron line is directly related to the $\pi$-$\pi$$\^$*/ energy gap of the molecule which plays an important role in organic electroluminescent materials. The molecular orbitals of Alq$_3$ and TPD and their major components, quinolime and benzene, have been calculated with the AMI semi-empirical method. The amount of the plasma-dominated loss of Alq$_3$ and TPD, which has to do with the delocalization of electrons through the molecule, was about 24 eV, alike in both cases. The main peak of the C 1s shake-up spectrum of Alq$_3$ and TPD, however, was 5.2 eV and 6.8 eV respectively. It was found that the main shake-up peak reflects more the local $\pi$\longrightarrow$\pi$$\^$*/ transition of quinoline and benzene component rather than the excitation of the whole molecule of Alq$_3$ and TPD. The C 1s shake-up spectra, however, revealed some correlation with the optical energy gap of the organic eletroluminescent materials.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.120.2-120.2
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• 2011

The improvement of solar energy-to-electricity conversion efficiency has continued to be an important research area of dye-sensitized solar cells (DSSCs). The mechanism of DSSCs is based on the injection of electrons from the photoexcited dye into the conduction band of nanocrystalline TiO2 or ZnO. Thus, the electronic structures, such as HOMO, LUMO, and HOMO-LUMO band gaps of dye moleculed in DSSC are deeply related to the electron transfer by photoexcitation and redox potential. Organic dyes, because of their many advantages, such as high molar extinction coefficients, convenience of customized molecular design for desired photophysical and photochemical properties, inexpensiveness with no transition metals contained, and environment-friendliness, are suitable as photosensitizers for DSSC. We believe that practically useful organic dye photosensitizers can be produced by exploiting electron donor/acceptor system with proper length of ${\pi}$-conjugation in a chromophore to control the absorption wavelength and enhance the photovoltaic performance. In this research, We designed and synthesized organic dyes also investigated the photoelectrochemical properties of a series of ionic dyes in DSSCs.

• 한국토양환경학회지
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• 제5권1호
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• pp.65-73
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• 2000

계면활성제를 사용하여 토양에 존재하는 소수성 유기오염물질을 제거하는 방법이 많이 연구되어져 왔다. 본 연구에서는 계면활성제의 구조적 차이에 따른 오염물질의 용해도 증가 효율을 평가하기 위하여 기존 계면활성제와는 다른 구조를 가진 계면활성제들을 가지고 비교·실험하였다. 그 결과 쌍둥이형 계면활성제(gemini surfactant)인 DADS12가 가장 용해도 증가율이 높게 나타났으며 머리가 두 개인 쌍두형 계면활성제(dianionic surfactant)가 일반 계면활성제인 SDDBS보다 적은 용해도 증가를 나타내었다. 이는 계면활성제의 유기탄소분율이 큰 것일수록 용해도 증가가 크고 계면활성제의 구조적 특성에 따른 마이셀의 형태나 구조에 크게 영향을 받지 않으며, 오염물질과 계면활성제 분자에다 존재하는 벤젠 고리간의 상호 인력 작용이 거의 일어나지 않거나 아주 미미한 것으로 보이며, 이에 따라 나프탈렌과 휘난트렌의 경우 오염물질의 제거 기작이 주로 마이셀 내부에 형성된 소수성 pseudophase로 오염물질이 흡수되는 것으로 추측된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.57-60
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• 2002

In generally, the guest-emitter doped system has been reported to give a bright electroluminescence(EL). The purpose of using doped system is to improve for increasing lifetime and efficiency, and tuning multicolor light. This indicates an enhanced electron-hole recombination rate in emitting layer. The purpose of this study is to obtain the high performance EL devices for flat panel display with red emission. We fabricated EL devices using the guest-host system. where DCM derivatives were taken as a dopant. The devices are fabricated in multilayer system with various concentration of the dopant (red light emitting dye). We measured the I-V characteristics and EL spectra from these devices. and we compared with photoluminescence(PL) quantum yield among the DCM derivatives. The emission mechanism of devices is participated in energy transfer. The energy transfer from these hosts to DCM generates luminescence spectra that vary from yellow red to red, depending on DCM derivatives. Absorption and emission spectra of organic materials composing the devices depend on the emission materials doped with the DCM derivatives. We demonstrated that the high EL efficiency can be achieved by doping host material with DCM derivatives and molecular steric structures

• 한국전기전자재료학회논문지
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• 제16권5호
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• pp.409-417
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• 2003

We have studied electrical properties and luminous efficiency of organic light-emitting diodes(OLEDs) with different buffer layer and cathodes in a temperature range of 10 K and 300 K. Four different device structures were made. The OLEDs are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris(8-hydroxyquinolinato) aluminum(III) (Alq$_3$) as an electron transport and omissive layer, and poly(3,4-ethylenedioxythiophene) :poly (styrenesulfonate) (PEDOT:PSS ) as a buffer layer. And LiAl was used as a cathode. Among the devices, the ITO/PEDOT:PSS/TPD/Alq$_3$/LiAl structure has a low energy-barrier height for charge injection and show a good luminous efficiency. We have got a highly efficient and low-voltage operating device using the conductive PEDOT:PSS and low work-function LiAl. From current-voltage characteristics with temperature variation, conduction mechanisms are explained SCLC (space charge limited current) and tunneling one. We have also studied energy barrier height and luminous efficiency at various temperature.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권3호
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• pp.115-118
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• 2005

Currently, molecular devices are reported utilizing active self-assembled monolayers (SAMs) containing the nitro group as the active component, which has active redox centers [1]. SAMs are ordered molecular structures formed by the adsorption of an active surfactant on a solid surface. The molecules will be spontaneously oriented toward the substrate surface and form an energetically favorable ordered layer. During this process, the surface-active head group of the molecule chemically reacts with and chemisorbs onto the substrate In this paper, the electrical properties of the 4'4- di(ethynylphenyl)-2'-nitro-1-benzenethiolate was confirmed. This material is well known as a conducting molecule having possible application to molecular level negative differential resistance (NDR) device. To deposit the self-assembly monolayers onto the gold electrode, the prefabricated Au(1 l l) substrates were immersed into 0.5[mM/l] self-assembly molecule in THF solution. Then, the electrical properties and surface morphologies of 4' 4-di(ethynylphenyl)-2' -nitro-1-benzenethiolate were measured by using the ultra-high vacuum scanning tunneling microscopy (UHV-STM).