• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.154-157
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• 2006

ITO(indium tin oxide)/glass 기판 위에 PEDOT:PSS[poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)]와 PVK[poly(N-vinyl carbazole)] 고분자 물질을 정공 주입 및 수송층으로, 발광층으로 PFO-poss[Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with POSS]를 사용하여 스핀코팅법과 열 증착법으로 ITO/PEDOT:PSS/PVK/PFO-poss/LiF/Al 구조의 고분자 발광 다이오드를 제작하였다. PFO-poss 유기발광 층의 열처리 조건 (온도, 시간)이 PLED 소자의 전기적, 광학적 특성에 미치는 영향을 조사하였다. 1 wt%의 농도를 갖는 PFO-poss 유기물 발광 층을 200C 온도로 3시간 열처리 할 경우 11 V 인가전압에서 $1497\;cd/m^2$의 최대 휘도를 나타내었다. 동일온도에서 열처리 시간을 1시간에서 3시간으로 증가시킬 경우 휘도의 증가와 함께 발광 개시온도가 감소하는 경향을 보여주었다. 또한 열처리 온도와 시간을 증가시킬 경우 제2발광피크인 excimer 피크가 크게 나타났으며 청색에서 황색 발광 쪽으로 천이되는 경향을 나타내었다.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.929-932
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• 2014

We explored interfacial electronic structures in indium tin oxide (ITO)/DNTPD/N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) layer stack in an OLED to clarify the real role of an aromatic amine-based hole injection layer, DNTPD. A hole injection barrier at the ITO/DNTPD interface is lowered by 0.20 eV but a new hole barrier of 0.36 eV at the DNTPD/NPB is created. The new barrier at the DNTPD/NPB interface and its higher bulk resistance serve as hole retardation, and thus those cause the operation voltage for the ITO/DNTPD/NPB to increase. However, it improves current efficiency through balancing holes and electrons in the emitting layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.469.1-469.1
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• 2014

일반적으로 유기전자소자의 제작에 있어서 Indium tin oxide (ITO)는 뛰어난 전기 광학적 특성을 바탕으로 가장 보편적으로 사용되는 투명전극이다. 특히 유기태양전지(Organic Photovoltaic, OPV)나 유기발광디스플레이(Organic Light Emitting Device)는 ITO 위에 PEDOT:PSS 층을 형성하여 HOMO, LUMO를 조절하고 효율을 향상시키는 역할을 수행하고 있다. 특히 ITO 위의 PEDOT:PSS는 사용되는 용제의 종류나 첨가제 등에 따라 특성이 크게 영향을 받는다. 이때 PEDOT:PSS는 일반적으로 강산성을 띄게 됨으로써 유기전자소자의 장시간 안정성을 저하시키는 원인으로 작용한다. 본 연구에서는 각각 다른 pH level을 가진 PEDOT:PSS의 시간 경과에 따라 투과도와 면저항을 측정하고 각각의 PEDOT을 사용하여 유기태양전지 소자를 제작하였다. 소자제작 30일 경과 후 소자의 효율이 감소하기는 하였으나 그 변화가 일반적으로 사용되는 pH 2의 감소보다 현저히 적었음을 알 수 있다. 이러한 pH 변화가 이를 적용한 투명전극 필름의 전기 광학적 특성인 투과도 면저항 등에는 영항을 거의 미치지 않으면서도 OPV의 효율 변화에는 큰 차이를 보이는 것을 알 수 있다.

• Rapid Communication in Photoscience
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• v.2 no.3
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• pp.79-81
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• 2013

A novel method of fabricating polythiophene-gold nanoparticle composite film electrodes for photoelectric conversion is demonstrated. The method includes electrodeposition of gold and electropolymerization of 2,2'-bithiophene onto an indium-tin-oxide (ITO) electrode. First, electrodeposition of gold onto the ITO electrode was carried out with various repetition times of pulsed applied potential (0.25 s at -2.0 V vs. Ag/AgCl) in an aqueous solution of $HAuCl_4$. Significant progress of the number density of deposited gold nanoparticles was confirmed from scanning electron micrographs, from 4 (1 time) to 25% (15 times). Next, electropolymerization of 2,2'-bithiophene onto the above ITO electrode was performed under controlled charge condition (+1.4 V vs. Ag wire, 15 $mC/cm^2$). Structural characterization of as-fabricated films were carried out by spectroscopic and electron micrographic methods. Photocurrent responses from the sample film electrodes were investigated in the presence of electron acceptors (methyl viologen and oxygen). Photocurrent intensities increased with increasing the density of deposited gold nanoparticles up to ~10%, and tended to decrease above it. It suggests that the surplus gold nanoparticles exhibit quenching effects rather than enhancement effects based on localized electric fields induced by surface plasmon resonance of the deposited gold nanoparticles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.225-225
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• 2008

ITO (Indium-tin oxide) 박막은 평판디스플레이, 유기발광소자, 박막태양전지 등 다양한 광전자소자의 투명전극으로 폭 넓게 이용되고 있다. 하지만 Si 박막태양전지의 투명전극에 요구되는 특성으로는 가시광 영역에서의 고투과율 및 고전도도 외에, 수소 플라즈마 분위기에서의 화학적 고안정성이 강하게 요구된다. 왜냐하면, 최근 Si 박막태양전지의 고효율화를 위해 미결정질 Si 박막 및 나노결정 Si 박막이 이용되고 있는데, 이러한 박막은 Si 원료가스를 고농도의 수소가스로 희석한 공정조건에서 플라즈마 CVD 증착기술을 이용하여 제조되기 때문에 투명 전극재료가 화학적으로 안정하지 않으면 계면특성의 열화로 인해 태양전지 효율이 저하되는 요인으로 작용하기 때문이다. 본 연구에서는 박막태양전지용 ITO계 투명전극의 수소 플라즈마에 대한 물리적 특성 변화를 조사하기 위하여 combinatorial sputter를 이용해 Ga 및 Zn의 도핑량을 연속적으로 변화시킨 ITO 박막을 제조하였고, $H_2$ plasma 중에 일정 시간 노출 시킨 후 박막의 물리적 특성 변화를 관찰하였다.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.294-300
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• 1995

The photoelectrochemical behavior of polypyrrole films on Pt, glassy-C and indium tin oxide(ITO) under illumination was studied in aqueous solution containing a redox couple such as I-/I2 or Fe(CN)64-/Fe(CN)63-. Polypyrrole(PPy) was coated on Pt, glassy-C and ITO electrodes using electrochemical polymerization of pyrrole by potentiostatic method. Illumination of the PPy film results in the increase of cathodic and anodic currents at redox potentials of the redox species. These enhanced currents are caused both by the semiconductor characteristics of PPy and by the photothermal acceleration of redox reaction at PPy-electrode surface, and are dependent on the pH of redox solutions and the dopants in PPy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.55-60
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• 2018

Transparent conductive thin films (TCFs) are essential materials for solar cells, organic light-emitting diodes, and display panels. Indium tin oxide (ITO) is one of the most widely used commercial materials to create TCFs'; however, new materials that can possibly replace ITO at a lower cost and/or those possessing mechanical flexibility are urgently needed. Silver nanowire (AgNW) is one of those promising materials, as it is less expensive and possesses superior mechanical flexibility as compared to ITO. We used AgNW and sol-gel ZnO to fabricate composite thin films by spray coating. We propose two spray-coating methods: the 'metal-organic chemical vapor deposition (MOCVD)/AgNW' method and the Mixture method. These two methods are expected to be commercialized for high-quality and low-cost products, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.473-476
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• 2003

This paper shows necessity of encapsulation layer to maximite flexibility of brittle indium-tin-oxide (ITO) on polymer substrates. And, Young's modulus (E) of encapsulation layer have an significant effect on external bending stress and the coefficient of thermal expansion (CTE) of that have a significant effect on internal thermal stress. To compare magnitude of total mechanical stress including both bending stress and thermal stress, the mechanical stress of triple-layer structure (substrate / ITO / encapsulation layer or substrate / buffer layer / ITO) can be quantified and numerically analyzed through the farthest cracked island position. As a result, it should be noted that multi-layer structures with more elastic encapsulation material have small mechanical stress compared to that of buffer and encapsulation structure of large Young's modulus material when they were externally bent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.615-616
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• 2005

Carbon Nanotubes (CNT) on flexible indium tin oxide (ITO) PET films were prepared for dye-sensitized solar cell (DSSC). These CNTs were prepared by spray coating method for various amount of light transparency. Also, Pt counter electrode was prepared by electro deposition method. All $TiO_2$ electrodes were deposited on ITO-PET films by spray coating method. Micro structural images show that CNT counter electrodes prepared by spray-coating have more dense structure with increasing spraying time (0 to 60 seconds). DSSC consisting of $TiO_2$ electrode and CNT counter electrode was fabricated with various amount of light absorption. DSSC have higher light energy conversion efficiency with increasing the thickness of CNT counter electrode. CNT counter electrode is at least compatible to that of CNT counter electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.399-400
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• 2007

In this work, we have investigated the characteristics of the phosphorescent OLED and flexible OLED fabricated on IZTO/glass and IZTO/PET anode film grown by magnetron sputtering, respectively. Electrical and optical characteristics of amorphous IZTO/glass anode exhibited similar to commercial ITO anode even though it was deposited at room temperature. In addition, the amorphous IZTO anode showed higher work function than that of the commercial ITO anode after ozone treatment for 10 minutes. Furthermore, a phosphorescent OLED fabricated on amorphous IZTO anode film showed improved current-voltage-luminance characteristics, external quantum efficiency and power efficiency in contrast with phosphorescent OLED fabricated on commercial ITO anode film. This indicates that IZTO anode is promising alternative anode materials for anode in OLEDs and flexible OLEDs.