• 한국응용과학기술학회지
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• 제19권1호
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• pp.49-55
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• 2002

We carried out this experiment to observe electrochemical properties for LB films of phospholipid(Dilauroyl-L-${\alpha}$-Phosphayidylcholine) and 4-octyl-4'-(5-carboxypentamethylene-oxy)azobenzene mixture by the cyclic voltammetry. LB films of 8A5H and 8A5H-DLPC(1:1, 2:1) were deposited by using the Langmuir-Blodgett method on the ITO glass. We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference elect rode, a platinum wire counter electrode and LB film-coated ITO working electrode measured in 0.1, 0.5, and 1.0 mol/L $NaClO_{4}$ solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a result, LB films of 8A5H 8A5H-DLPC appeared irreversible process caused by only the oxidation current from the cyclic voltammogram.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.352-353
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• 2007

The spectrum for $0_{\circ}$, $90_{\circ}$-polarized light coincides with the spectrum for non-polarized light and also with the spectrum was observed in the LB film deposited using a fresh solution. And, the formation and dissociation of J-aggregates, anisotropic behavior was no longer observed in the heat treated merocyanine dyes LB films. But, in the optical absorption spectra of same LB films by UV irradiation at room temperature, their were observed only dissociation of J-aggregates, that is decrease of absorbance peak without change spectral shape. On the other hand, in the case of optical absorption spectra of the LB films by the heat treatment at $70^{\circ}C$ in the air, both of the shifted absorption bands decay and a monomer absorption peak of about 530 nm appears instead.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.225-227
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• 1994

The second-order nonlinear optical effect, especially the second harmonic generation, in Langmuir-Blodgett(LB) films have get much attention over the past few years. For second harmonic generation(SHG) of the ultrathin organic films, the multilayer structure of the film should have the noncentrosymmetric arrangements of molecules. The Langmuir-Blodgett technique can result in the production of thin films of precisely controlled dimensions and structure. In this paper, n-octadecyl 4-(4'-nitrophenylazo)-1-naphthyl ether, ONNE(azohenzene derivative), was synthesized and the optical properties of ONNE was studied. Nonccntrosymmctric Z-type LB films of ONNE were prepared and SHG intensity of the film were measured. The structural characteristics of floating monolayer(L film) and LB film of ONNE were discussed with $\pi$-A isotherm. UV-visible absorption spectroscopy and spectroscopic ellipsometry. The polarized UV-visible absorption spectroscopy and SHO intensity suggest the molecular orientation in LB film.

• Macromolecular Research
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• 제16권4호
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• pp.367-372
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• 2008

We fabricated tetra(5-n-nonyl-8-tert-butyl-2,3-pyrazino[2,3-b]indolo)porphyrazinato copper(II) (Cu-Pc-$C_8$) Langmuir-Blodgett (LB) films. We further investigated the influence of arachidic acid (AA) as a transfer promoter, as well as the effect of dipping speed, on the deposition of the films on hydrophilic and hydrophobic substrates. In the case of pure Cu-Pc-$C_8$ LB deposition on a hydrophilic substrate, the transfer ratio was close to one for up-stroke depositions, but the previously deposited film was peeled off and re-spread onto water at down-stroke depositions. Whereas the stability of the Cu-Pc-$C_8$ LB films was not improved by AA addition on hydrophilic substrates, the deposition of Cu-Pc-$C_8$ was significantly improved by the presence of AA on a hydrophobic substrate. The AA-assisted deposition had transfer ratio of close to 1 and was essentially stable up to 10-layer depositions. Comparison of the UV-visible spectrum of a Cu-Pc-$C_8$/AA LB film with that of Cu-Pc-$C_8$/AA solution in dichloroethane revealed that the Soret and Q bands for the Cu-Pc-$C_8$/AA LB film were broadened and red-shifted due to the aggregation of phthalocyanines upon assembly in the LB film.

• 한국응용과학기술학회지
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• 제19권2호
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• pp.73-78
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• 2002

The polyimide(PI) Langmuir-Blodgett(LB) ultra thin films were prepared by imidizing the PAAS LB films of PMDA and benzidine system with a thermal treatment at $250^{\circ}C$ for 30min, where the PAAS LB films were formed on substrates by using LB technique. The thicknesses of one layer of PAAS and PI LB film that deposited at the surface pressure of 27mN/m were 20.9 and 4A, respectively. At low electric field, ohmic conduction($I^{\propto}$ V) was observed and the calculated electrical conductivity was about $4.23{\times}10^{-15}{\sim}9.81{\times}10^{-15}S/cm$. The dielectric constant of LB film was about 7.0.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1722-1724
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• 1996

Enhancing the electrical conductivity of the ultrathin organic films is one of the important factors for the development of molecular electronic devices. The Langmuir-Blodgett(LB) technique has recently been attracted as out of the ways of deposition ultrathin films. We have studied manufacturing conditions and physical properties of Hexadecyl Dipyridinium-$(TCNQ^-)_2$ LB films made by Kuhn type apparatus. A ${\pi}-A$ isotherm shows that a limiting area is around $180{\AA}^2/molecule$ and a proper surface pressure for a deposition is around 22mN/m. A transfer ratio shows that Hexadecyl Dipyridinium-$(TCNQ^-)_2$ is able to be deposited as an Y-type. UV /visible absorption spectra shows that TCNQ dimer peak is apeared at about 600nm in LB films. In solution, $TCNQ^-$ peak is observed at about 400nm and charge transfer band at $830{\sim}900nm$. A horizontal conductivity of the Hexadecyl Dipyridinium-$(TCNQ^-)_2$ LB film is about $10^{-7}(S/cm)$.

• 대한전기학회논문지
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• 제44권4호
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• pp.496-501
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• 1995

The N $O_{2}$ gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett (LB) films of Copper-tetra-tert-butylphthalocyanine (CuTBP), Dilithium phthalocyanine (Li$_{2}$Pc), N-docosylpyridinium TCNQ(C$_{22}$Py(TCNQ)), Polyamic acid alkylamine salts (PAAS). The optimum conditions for a film deposition were obtained through a study of .pi.-.ALPHA. isotherms and the deposited film status was confirmed by electrical and optical methods such as UV/visible absortion spectra, thickness measurements by ellipsometry, and electrical capacitances. A response of the LB films to the N $O_{2}$ gas was measured by a change of the electrical conductivities when the film is exposed to the gases. The CuTBP LB film shows the biggest change of the electrical conductivities when it is exposed to the N $O_{2}$ gases. And the order of gas-detection performance is the following;Li$_{2}$Pc, $C_{22}$Py(TCNQ), and PAAS LB films. Especially, the CuTBP and Li$_{2}$Pc LB films not only show the bigger change in the electircal conductivities when exposed to the gas, but return to the original state when the gas is desorbed.d.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.97-100
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• 1998

We studied on the ultra thin L-${\alpha}$-DLPC by LB method. The $\pi$-A isotherm of the L-${\alpha}$-DLPC was measured at the air-water interface varying with the compressing speed and amounts of solutions for spreading. The molecular arrangement of deposited films were evaluated by measuring the absorption with the UVspectrometer. And we made structures of metal(Au)/L-${\alpha}$-DLPC/Metal(Au) and examined electron through L-${\alpha}$-DLPC LB films by means of current-voltage(I-V) measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.198-201
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• 1997

The new system for identification of organic vapours and analysis method of mechanism between organic vapours and sensitive materials were attempted using the resonant resistance and resonant frequency of Quartz Crystal Analyzer (Q. C. A.). The resonant resistance shift means rheological changes in sensitive LB films occurred by the adsorption of organic vapours, while the resonant frequency shift represent the mass of organic vapour loaded in or on the sensitive LB films. It is thought that we can obtain more accurate response mechanism of organic vapour using the resonant frequency and resonant resistance diagram. The polymeric sensitive material were quantitively depositied using the LB method. In the experimental results, the adsorption behavior of organic vapour response can be decided by two type ; surface adsorption and penetration into sensitive material. Organic vapours had different positions in the Frequency-Resistance (F-R) diagram as to the kinds and concentrations of organic vapours. Thus F-R diagram can be applied to the development of one channel gas sensing system using the Quartz Crystal Analyzer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.38-42
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• 1996

The pressure-area isotherm of monolayer at the air-water interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystal by conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) film on quartz slides and spectrum of monolayer formed on quartz crystal have been measured. The photoisomerization of the long-chain fatty avid containing azobenzene were obtained by the application of UV and visible light. The reversibility of photoisomerization were more clear difference when the number of C$\_$n/ increased. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of C$\_$n/ increased, A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were also obtained by application of UV and visible light. So the LB film of long-chain fatty acid containing azobenzene has possibility to being applies to functional molecular devices such as photomemory and light switching.