• Korean Journal of Materials Research
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• v.10 no.8
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• pp.564-568
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• 2000

Langmuir-Blodgett(LB) 법은 미래의 분자전자소자를 위한 가장 유력한 수단이며, 이러한 분자박막 소자는 그 성질이 분자는 배향에 영향을 박데 되므로 현재 새로운 물질을 이용하여 분자전자소자의 제작에 있어 관심을 모으고 있다. 본 연구에서는 (N-docosyl quinolinium)-TCNQ(1:2) 전하 이동 착물 LB 막의 분자 배향을 UV/vis 편광흡수 스펙트럼과 FT-IR transmission 및 reflection-absorption 스펙트럼의 흡수강도를 비교하여 정량적으로 평가하였다. 그 결과 TCNQ의 transition dipole moment의 각은 약 56~58。 였으며, 알킬 고리의 경사각은 약 11.1~13。였다. 제작된 Z-형 LB 막의 표면은 고압에서 중앙 높이 차가 3~4$\AA$으로 평탄하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.53.1-56
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• 2000

Langmuir-Blodgett(LB) technique is the best candidate for the future molecular electronic devices. But, these molecular thin film devices require the bulk properties that are influenced by the molecular orientations. So, this is of current interest in molecular electronic device fabrications of new materials. In this study, quantitative evaluation of molecular orientation in LB films of PAAS was performed by comparing the absorption intensities of the FT-IR transmission and reflection-absorption spectra and the polarized UV/visible absorption spectra. It was found that the polar angle($\theta$) of the dipole moment is about 68$^{\circ}$and the tilting angle of the alkyl chain is about $11.5^{\circ}$ .

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.53-56
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• 2000

Langmuir-Blodgett(LB) technique is the best candidate for the future molecular electronic devices. But, these molecular thin film devices require the bulk properties that are influenced by the molecular orientations. So, this is of current interest in molecular electronic device fabrications of new materials. In this study, quantitative evaluation of molecular orientation in LB films of PAAS was performed by comparing the absorption intensities of the FT-IR transmission and reflection-absorption spectra and the polarized UV/visible absorption spectra. It was found that the polar angle( $\theta$ ) of the dipole moment is about 68$^{\circ}$ and the tilting angle of the alkyl chain is about 11.5$^{\circ}$

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.79-87
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• 1997

In this study, MEH-PPV was synthesized and MEH-PPV and its mixtures with PMMA were deposited on substrates with Langmuir-Blodgett(LB) technique and their photoluminescent char acteristics were investigated using UV-Vis absorption spectroscopy, and photoluminescence(PL) measurements. The surface morphology of the LB films of MEH-PPV and its mixture with PMMA were investigated using Atomic Force Microscopy(AFM). Electroluminescent devices using LB films were fabricated with Al and ITO as a top and bottom electrode, respectively, and their I-V characteristics were investigated.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.303-311
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• 1994

Optimum conditions for the deposition of N-docosylquinolium-TCNQ ultrathin organic films using the Langmuir-Blodgett etchnique and the molecular orientation and alignment of the LB films were studied. The $\pi$-A isotherm of the N-docosylquinolium-TCNQ was measured at the air-water interface varying with the subphase temperature, subphase pH, compressing speed and amounts of solutions for spreading. The LB film was deposited under the surface pressure of 30mN.m and 45mN/m and other deposition conditions. The molecular orientation and alignment of the LB films were studied by the polarization absorption technique. The $\pi$-A isotherm showed that the stable N-docosylquinolium -TCNQ monolayer was formed on the water surface at the condition of 25$^{\circ}C$,pH 5.6, molecular density of 2.1${\times}$10S014T~2.6${\times}$10S014T/cmS02T. The LB film was deposited under the surface pressure of 45mN/m had better packing density, orientation and alignment than the film of 30mN/m.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.601-604
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• 1999

Electroluminescence(EL) devices based on organic thin films have attracted lots of interests in large-area light-emitting display. Recently, many EL researcher have interested a new emissive organic material. In this study, light-emitting organic electroluminescent devices were fabricated using Langmuir-Blodgett(LB) technique with new emissive organic material. This new emissive organic material were synthesis by our teams and we called PECCP [poly(3,6-N-2ethylhexyl carbazoly cyanoterephthalidene)] which has strong electron donor group and electron acceptor group in main chain repeat unit. This material has good solubility in common organic solvent such as chloroform. THF, etc. and has a good stability in air. In here, the new emissive material is applied to Langmuir-Blodgett(LB) method because our new material has a good stability in air. Optimum conditions of film deposition were examined by a surface pressure-area( $\pi$ -A) isotherms with various factors. The LB film were deposited on a indium Tin Oxide(ITO) glass. We were investigated by measuring current-voltage(I-V) characteristics. Also we were measured the UV/visible absorption at about 410nm and PL spectrum at about 530nm. We are attempt to the electroluminescence device properties of the new emissive material by Langmuir-Blodgett(LB) technique.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.820-825
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• 1998

We deposited stearic acid LB films by using Langmuir-Blodgett (LB)method and investigated anisotropy electrical conduction characteristics by I-V measurement for horizontal direction and vertical direction. Also, we measured gad response between deposited LB films and organic gas for various temperature(0~8$0^{\circ}C$) by 9MHz At-cut quartz crystal microbalance. The LB films have electrical conduction characteristics such as semiconducting and insulating properties. The is, the conductivity of LB films for the horizontal and vertical direction is about 10\ulcornerS/cm and 10\ulcorners/cm, respectively. the frequency shift of stearic acid LB films for the organic gases depended on the mass change by the surface adsorption and the inner penetration to the sensing films. The resonant frequency shift of the quartz crystal microbalance for temperature properties of LB films is thought to the effect of the rearrangement or the damage pf LB films above the melting point and the mobility increasement of the organic gas by the temperature rising.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.572-575
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• 2000

The highly efficient photoelectric conversion of chlorophyll a (Chl a) monolayers and multilayers was investigated. Using the Langmuir-Blodgett (LB) technique, Chl a monolayers and multilayers were fabricated onto optically transparent electrode, such as ITO glass. The photocurrent could be observed according to the light illumination. The action spectrum of the Chl a LB films was well consistent with its absorption spectrum. The possible application of the proposed system as a constituent of the artificial color recognition device was suggested.

• Electrical & Electronic Materials
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• v.11 no.10
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• pp.78-80
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• 1998

Metallo-phthalocyanines(MPcs) are very sensitive to toxic molecules such as electron affinitive NO2 gas and also chemically and thermally stable since losts of MPcs have been studied for the potential chemcial gas sensors for $NO_2$ using their electrical conductivity. In this study, thin films of octa-dodecyloxy copper -phthalocyanine were prepared by Langmuir-Blodgett(LB) method and characterized by using UV/Vis absorption spectroscopy, and ellipsometry. It was found that the proper transfer surface pressure for the film deposition was 25mN/m and the limiting area per molecule was $112\AA$/molecule. The film thickness of one layer was $64\AA$. Current-voltage(I-V) characteristics of these films were investigated as a function of film thickness.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.1
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• pp.35-42
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• 1989

Electrical properties of both a monolayer at the air/water interface and Langmuir-Blodgett films sandwiched between aluminum electrodes are studied using a current-measuring technique. A change in induced charges on an electrode suspended in the air was measured in combination with the surface area isotherm in the electrical measurement of the monolayer. A change in induced charges on an electrode is measured while heating the sample in the electrical measurement of the LB films. From both measurements, we elucidated that a spontaneous polarization plays very important role in the electrical properties of both a monolayer at the air/water interface and LB films sandwiched between aluminum electrodes.