• 반도체디스플레이기술학회지
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• 제6권2호
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• pp.19-23
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• 2007

The blue emitting OLEDs using TMP-BiP[(4'-Benzoylferphenyl-4-yl)phenyl-methanone-Diethyl(biphenyl-4-ymethyl) phosphonate] host and DJNBD-1 dopant have been fabricated and characterized. In the device fabrication, 2-TNATA [4,4',4"-tris(2-naphthylphenyl-phenylamino)-triphenylamine] as a hole injection material and NPB [N,N'-bis(1-naphthyl)N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] as a hole transport material were deposited on the ITO(indium tin oxide)/glass substrate by vacuum thermal evaporation method. Followed by the deposition, blue color emission layer was deposited using TMP-BiP as a host material and DJNBD-1 as a dopant. Finally, small molecule OLEDs with structure of $ITO/2-TNATA/NPB/TMP-BiP:DJNBD-l/Alq_3/LiF/Al$ were obtained by in-situ deposition of $Alq_3$, LiF and Al as the electron transport material, electron injection material and cathode, respectively. The effect of dopant into host material of the blue OLEDs was studied. The blue OLEDs with DJNBD-1 dopant showed that the maximum current and luminance were found to be about 34 mA and $8110\;cd/m^2$ at 11 V, respectively. In addition, the color coordinate was x=0.17, y=0.17 in CIE color chart, and the peak emission wavelength was 440 nm. The maximum current efficiency of 2.15 cd/A at 7 V was obtained in this experiment.

• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.7-11
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• 2008

ITO (Indium Tin Oxide) thin films have been extensively studied for OLED devices because they have high transparent properties in the visible wavelength and a low electrical resistivity. These ITO films are deposited by rf-magnetron sputtering under different ambient gases (Ar, Ar+$O_2$ and Ar+$H_2$) at $300^{\circ}C$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon has been changed from 0.5sccm to 5sccm and from 0.01sccm to 0.25sccm respectively. The resistivity of ITO film increased with increasing flow rate of $O_2$ under Ar+$O_2$ while it is nearly constant under Ar+$H_2$. And the peak of ITO films obtained (222) and (400) orientations and the average transmittance was over 80% in the visible range. The OLED device fabricated with different ITO substrates made by configuration of ITO/$\alpha$-NPD/Alq3/LiF/Al to elucidate the performance of ITO substrate for OLED device.

• 반도체디스플레이기술학회지
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• 제16권1호
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• pp.40-44
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• 2017

The effect of weak dielectric silicone dioxide($SiO_2$) embedded in polyfluorene(PFO) emitting layer of polymer-based multi structure OLED was investigated. Indium tin oxide(ITO)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/poly(9,9-di-n-octylfluorenyl-2,7-diyl)(PFO)/2,2,2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)/aluminum(Al) structure OLED was fabricated by spin-coating method. Applied electric field causes some effect on $SiO_2$ in PFO layer. Thus, interaction between polymers and affected $SiO_2$ might generate electrical and luminance properties change. Experimental results, show the reduced threshold voltage of 6 V(from 23 V to 17 V). The maximum current density was rather increased from $71A/m^2$ to $610A/m^2$ and maximum brightness was also increased from $7.19cd/m^2$ to $41.03cd/m^2$, 9 and 6 times each. Additionally we obtained colour broadening result due to the increasing of blue-green band emission. Consequently we observed that electrical and luminance properties are enhanced by adding $SiO_2$ and identified the possibility of controlling the emission colour of OLED device according to colour broadening.

• 대한의용생체공학회:의공학회지
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• 제36권6호
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• pp.283-290
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• 2015

We proposed blink based online speller for the locked-in syndrome (LIS) patients, paralyzed in nearly all voluntary muscles expect for the eyes, with a simple and easy-to-use eye blink detection glasses. Electrooculogram (EOG) is the golden standard method of eye movement or blink measurement with Ag/AgCl electrodes. However, this method has several drawbacks such as skin irritation and dehydration of conductive gel. To resolve the shortcomings, we used a blink detection system based on a transparent capacitively coupled electrode, which is conductive indium tin oxide (ITO) films. The films make it possible to measure eye blink without direct skin contact and obstruction of field of view. We finally developed user-friendly blink based online speller with the blink detection system. To classify voluntary and non-voluntary blink, we used the double blink for command of the speller. The online speller experiment result with six healthy subjects shows that mean accuracy is 98.96% and letter per minute (LPM) is 4.73, which are better result by comparison with conventional P300 or auditory brain-computer interface (BCI) paradigm. The result of the experiment demonstrates the possibility of applying the proposed system as a communication method for the LIS patients.

• 한국응용과학기술학회지
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• 제20권2호
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• pp.94-100
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• 2003

We studied electrochemical characteristics of Langmuir-Blodgett(LB) films by using cyclic voltammetry with a three-electrode system. An Ag/AgCl as a reference electrode, a platinum wire as a counter electrode and LB film-coated indium tin oxide(ITO) as a working electrode were used to study electrochemical characteristics at a various concentration of $NaClO_4$ solution. LB films were reduced from initial potential to -1350 mV, continuously oxidized to l650mV and returned to the initial point. The scan rate was l00mV/s. The monolayer surface morphology of the LB film have been measured by Atomic Force Microscope(AFM). As a result, We comfirmed that the microscopic properties of LB film by AFM showed the good orientation of momolayer molecules and the thickness of monolayer was 3.5-4.lnm. The cyclic voltammograms(CV) of the ITO-coated glass showed the peak potentials for the reduction-oxidation reation. LB films of 4-octyl-4'-(5-carboxypentamethyleneoxy) azobenzene(8A5H) / L-${\alpha}$-phosphayidyl choline, dilauroyl(DLPC) seemed to be irreversible process caused by only the oxidation current from the cyclic voltammogram. The current of oxidatation increased at cyclic voltammogram by increasing 8A5H density in LB films. The diffusivity(D) of LB films increased with increasing of a 8A5H amount and was inversely proportional to the concentration of $NaClO_4$ solution.

• 한국표면공학회지
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• 제53권4호
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• pp.182-189
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• 2020

Indium tin oxide (ITO) used a transparent electrode of a photoelectric device has a low sheet resistance and a high transmittance. However, ITO is disadvantageous in that the process cost is expensive, and the process time is long. Silver nanowires (AgNWs) transparent electrodes are based on a low cost solution process. In addition, it has attracted attention as a next-generation transparent electrode material that replaces ITO because it has similar electrical and optical characteristic to ITO, it is noted as a. AgNW thin films are mainly produced by spin-coating. However, the spin-coating process has a disadvantage of high material loss. In this study, the material loss was reduced by using about 2~10 ㎕ of AgNW solution on a (25 × 25) ㎟ substrate using the shear-coating method. It was also possible to align AgNWs in the drag direction by dragging the meniscus of the solution. The electro-optical properties of the AgNW thin film were adjusted by changing the experimental parameters that the amount of AgNWs suspension, the gap between the substrate and the blade, and the coating speed. As a result, AgNW thin films with a transmittance of 90.7 % at a wavelength of 550 nm and a sheet resistance of 15 Ω/□ was deposited and exhibited similar properties to similar AgNW transparent electrodes studied by other researchers.

• 한국표면공학회지
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• 제39권5호
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• pp.206-209
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• 2006

Indium tin oxide (ITO) films were synthesized on polymer (PES, polyethersulfone) at room temperature by pulsed DC magnetron sputtering. By the control of introducing hydrogen to argon atmosphere, the resistivity of ITO films was obtained at $5.27\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$ without substrate heating in comparison with $2.65\;{\times}\;10{-3}\;{\Omega}{\cdot}cm$ under hydrogen free condition. ITO film synthesized at Ar condition was changed from amorphous to crystalline. These result from the enhancement of electron temperature in $Ar\;+\;H_2$ plasma, which induces the increase of ionization of target materials and argon. The dominant increase of ions such as In II and O II and neutral Sn I was monitored by optical emission spectroscopy (OES). Thermal energy required for the crystalline film formation is compensated by kinetic energy transfer through ion bombardments to substrate.

• 한국환경과학회지
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• 제14권8호
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• pp.801-810
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• 2005

The phosphor and ITO(Indium Tin Oxide) films for video phone tube (VPT) were simply prepared by the screen printing and thermal transfer methods. The increasing order of thermal firing of acrylic binder for phosphor and ITO was M6003 < M6664 < A/A 1919 < M500l < M670 1 and all mass of binders were perfectly decomposed at lower temperature than $400^{\circ}C.$ After thermal firing of phosphor paste, the residual of binder on the surface of phosphor could not be found by SEM. Aerosil as thickner provides the thixotropy property for phosphor paste but decrease the brightness of phosphor screen as residual after thermal firing. Since the thixotropy of M5001 binder without aerosil was shown and the storage modulus of phosphor paste by increasing the angular frequency was not nearly changed and the decrease of the storage modulus of phosphor paste by increasing the strain was remarkably shown. It was possible to prepare the phosphor paste which was predominant in the plate separation and the reproduction of pattern after the screen printing. Since the addition of dispersing agent to improve the printing process decreases the electrical conductivity and light transmission of ITa film, it could be found to be necessary the development of binder for phosphor paste that decreases the amount of dispersing agent possibly and does not use the aerosil as additive.

• 전기전자학회논문지
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• 제24권1호
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• pp.59-66
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• 2020

최근 휴대용 통신기기와 스마트 디스플레이의 결합은 휴대가 용이하고 이동을 하면서 모든 작업을 할 수 있다. 이에 본 논문에서는 휴대용 통신기기에서 저가격의 높은 투명전극을 찾기 위해 여러 가지 ITO(Indium Tin Oxide) 박막에 대해 연구하였다. ITO 박막은 DC 마그네트론 스펏터를 사용하였으며 1 분위기압을 1mTorr 증가 간격으로, 2 바이어스 전압은 10V 간격으로 변화시켜 측정하였다. 두께와 굴절율은 일립소미터를 사용하였으며 막의 단면과 표면의 형상은 주사전자현미경을 사용하여 조사하였다. 분석 결과를 통해 바이어스 전압이 300V 이상일 경우에 명확한 증착이 나타났으며 추가로 전압이 증가함에 따라 전체적으로 증착률이 증가하였다. 330V 조건에서 증착률이 가장 높았으며 뚜렷한 결정립이 관찰되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.411-412
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• 2008

We have studied a property change of organic light-emitting diodes (OLED) due to an indium tin oxide (ITO) surface reformation. The characteristics of OLED were improved by oxygen plasma processing of an ITO in this work. ITO is widely used as a transparent electrode in light-emitting devices, and the OLED device performance is sensitive to the surface properties of the ITO. The OLED devices with the structure of ITO/TPD(50nm)/$Alq_3$(70nm)/LiF(0.5nm)/Al(100nm) were fabricated, and the surface properties of ITO were investigated by using various characterization techniques. The oxygen plasma process of an ITO was processed by using RF power of 125W and oxygen partial pressure of $2\times10^{-2}$ Torr. The oxygen plasma processing of an ITO processed for 0/1/2/3/4min. Current-voltage-luminance characteristics of the devices show that turn-on voltage is 4V for 2min device and the luminance reaches about 27,000cd/$m^2$ for 4min device. The current efficiency shows that 3min device becomes saturated to be about 8cd/ A. They show that emission was from the $Alq_3$ layer, because the peak wavelength is about 525nm. View angle-dependent emission spectra show that the emission intensity decreases as the angle increases.