• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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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.

• 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.

• Macromolecular Research
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• v.16 no.4
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.8
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• pp.581-586
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• 1998

This paper describes athermally stimulated displacement current (TSDC) of arachidic acid(AA) and polyamic acid alkylamine salts(PAAS) Langmuir-Blodgett(LB) films, which is a precursor of polyimide(PI). The TSDC measurements of AA LB film were performed from temperature to about 11$0^{\circ}C$ at a rate of 0.2$^{\circ}C$/ｓ inside a vacuum chamber for a reference. And the TSDC measurements PAAS LB film were performed from room temperature to about 25$0^{\circ}C$ and temperature was increased at the same rate as that of AA LB film. They show that there are TSDC peaks at about 7$0^{\circ}C$ in the arachidic acid LB films, and at about 7$0^{\circ}C$ and 16$0^{\circ}C$ in the PAAs LB films. Results of these measurements indicate the one small peak at 7$0^{\circ}C$ is resulted from a softening of the alkyl group and the large peak at 16$0^{\circ}C$ is possibly due to dipole of C-O group in the PASS molecule. We have calculated the vertical component of the AA and PAAs L film out of the TSDC curves. It shows that the dipole moment of the AA LB film is about 70-mD at 7$0^{\circ}C$. And the dipole moment of PAAS LB film is about 040mD at 7$0^{\circ}C$ and about 200mD at 16$0^{\circ}C$ in the first measurement of TSDC. In the second measurement of TSDC of PASS LB film after cooling down to room temperature, the TSDC peaks are almost disappeared.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.131-136
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• 1995

Ultra-thin films of hexyltriphenylphosphonium-TCNQ(1:1) complex were formed on various substrates by Langmuir-Blodgett technique, where hexyltriphenylphosphonium-TCNQ(1:1) complex was synthesized by attaching hexyltriphenylphosphonium group to TCNQ. The reaction product was identified with FT-IR, and UV-Vis absorption spectroscopies. The formation of ultra-thin films of hexyltriphenylphosphonium-TCNQ(1:1) complex was confirmed also by FT-IR, and UV/Vis absorption spectroscopies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.831-834
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• 2000

Characteristics of organic light-emitting diodes(OLEDs) were studied with devices made by PECCP[poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene)] Langmuir-Blodget(LB) films. The emissive organic material was synthesized and named PECCP, which has a strong electron donor group and an electron accepter group in main chain repeated unit. The LB technique was employed to investigate the identification of the recombination zone in the ITO/PECCP LB films/Alq$_3$/Al structure by varying the LB film thickness. PECCP was considered as an emissive layer and Alq$_3$was used as an electron-transport layer. We measured current-voltage(I-V) characteristics, UV/visible absorption, PL spectrum, and EL spectrum of those devises.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.566-570
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• 2010

Electro-optic modulators based on 25 monolayer langmuir-blodgett films of vinylidene fluoride and trifluoroethylene, P(VDF-TrFE), were fabricated. The LB films were prepared by transferring the monolayers on to an ITO coated glass with a surface pressure of 5 dyne/cm by use of the langmuir-schaefer deposition method. Measurement of the electro-optic coefficient has been carried out using a simple reflection techique. The E/O coefficient was found to be 154.9 pm/V and that value remained stable for at least 50 days.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.111-114
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• 1995

This paper describes the imidization of PAAS(polyamic acid alkylamine salts) Langmuir-Blodgett (LB) films and the electrical properties of PAAS and polyimide(PI) LB films, The imidization conditons were investigated by TGA(Thermal Gravi-tational Analysis). FT-IR and UV/ visible absorption spectra. A thermal imidiczation was peformed at 300$^{\circ}C$ for 1 hour. The electrical properties of the PAAS and polymide LB films were measured by current-voltate(L-V) characteristics It shows that the electrical condcutivity of PL LB films is about 10 $\^$-15/S/cm which is two orders of magnetiude lower than that of the PAAS LB films A Schottky effect was also observed in both films.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.451-456
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• 2009

We carried out this experiment to observe an electrochemical properties for LB films of alkyl compounds by the cyclic voltammetry. Alkyl bromides was deposited by using the Langmuir- Blodgett method on the ITO glass. We measured to an electrochemical measurement by using cyclic voltammetry with a three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) in 0.5, 1.0, 1.5 and 2.0 N $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV. The scan rate were 100 mV/s. As a result, an electrochemical properties of the LB films of alkyl bromides appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of alkyl compounds amount.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.29-35
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• 2000

In this study, ultra-thin films of (N-docosyl quinolinium)-TCNQ(1:2) complex were prepared on the hydrophilic substrate by Langmuir-Blodgett(LB) technique. The characteristics of ${\pi}-A$ isotherms were studied to find optimum conditions of deposition by varying temperature of subphase, compression speed of barrier and amount of spreading solution. Using UV-vis spectra, capacitance and thickness, deposition of LB films was confirmed together with the thickness of the naturally oxidized aluminum film inside a device and dielectric constant of (N-docosyl quinolinium)-TCNQ(1:2) complex. The dielectric constant of LB film was about $4.59{\sim}5.58$. The electrical properties of (N-docosyl quinolinium)-TCNQ(1:2) complex were investigated at room temperature. The conductivity of this film measured by the direction of either vertical or horizontal axis was found to have a quite different value.