• ETRI Journal
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• v.29 no.6
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• pp.817-819
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• 2007

A low-stress organic polymer membrane is proposed as a deformable mirror that can be incorporated into a cellular phone camera to achieve auto focusing without motor-type moving parts. It is demonstrated that our fabricated device has an optical power of 20 diopters and can switch focus in 14 ms. The surface roughness of the organic membrane is measured around 15 nm, less than ${\lambda}$/20 of the visible light. With curve fitting, we found that the actuated membrane is almost parabolic in shape, which leads to less aberration than spherical surfaces. It is suitable for reflective-optics systems.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.25-29
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• 2011

Organic electroluminesencent device have been studied because of its easy fabrication and high brightness for plate panel display instead of CRT and LED. There are some device structure for full color filter system can be applicable to the full color application if the blue light organic electroluminesencent device(OELD) is developed. In this study, We have investigated electro-luminescent (EL) characteristics of organic EL device using Alq3, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.446-449
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• 2008

Organic light emitting diodes (OLEDs) with multiple organic layers were fabricated to obtain and to evaluate an equivalent resistance and an equivalent capacitance of OLED device. The staircase voltage with an increasing period and a constant period was designed and applied to the OLED. The resistance of OLED was found to decrease from $270\;k{\Omega}$ to $2\;K{\Omega}$ as applied voltage increased after turn on. The equivalent capacitance of OLED maintained unchanged at low voltage level and deceased after showing peak value as the applied voltage increased.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.243-246
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• 2008

Roll-printed organic thin-film transistors (OTFTs) were fabricated by gravure or flexography printing using patterned PDMS stamp with various channel lengths, silver pastes, coated polyvinylphenol dielectric, and jetted bis(triisopropyl-silylethynyl) pentacene semiconductor on plastic substrates. The roll-printed OTFT parameters were obtained: fieldeffect mobility of $0.1\;cm^2/Vs$, an on/off current ratio of $10^4$ and a subthreshold slope of 2.53 V/decade.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.40-45
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• 2008

We developed small molecular organic nonvolatile $4F^2$ memory cells using metal layer evaporation followed by $O_2$ plasma oxidation. Our memory cells sandwich an upper ${\alpha}$-NPD layer, Al nanocrystals surrounded by $Al_2O_3$, and a bottom ${\alpha}$-NPD layer between top and bottom electrodes. Their nonvolatile memory characteristics are excellent: the $V_{th},\;V_p$ (program), $V_e$ (erase), memory margin ($I_{on}/I_{off}$), data retention time, and erase and program endurance were 2.6 V, 5.3 V, 8.5 V, ${\approx}1.5{\times}10^2,\;1{\times}10^5s$, and $1{\times}10^3$ cycles, respectively. They also demonstrated symmetrical current versus voltage characteristics and a reversible erase and program process, indicating potential for terabit-level nonvolatile memory.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.269-272
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• 2000

In this paper, we was fabricated and analyzed a blue organic electroluminescent devices with the organic dye, such as 1,1,4,4-Tetraphenyl-1,3-butadi-ene(TPB). The device was made by simultaneously co-depositing two materials. The device structure was composed of the ITO glass, TPD, Alq$_3$doped TPB, and aluminum(A1) electrode. Carrier injection from the two electrodes was significant]y observed and the blue light in EL spectrum, with an emission maximum at 462nm, was triggered at a driving voltage of 11V.

• Vacuum Magazine
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• v.1 no.2
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• pp.24-29
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• 2014

Display is a key component in electronic devices. OLED is growing very fast recently due to the explosion of the smart phone market although still LCD is the dominating display technology in the display market at the moment. Also needs for the large area and high resolution TVs and flexible displays are increasing these days. Especially flexible display is expected to be one of the key technologies in mobile devices requiring small device size and large display size. Contrary to the conventional displays, flexible display requires organic materials for the substrate, the active driving element and also for the display element. Plastic film as a substrate, organic semiconductor as an active component of the transistor and organic light emitting materials or electronic paper as a display element are studied actively. In this article, mainly backplane technologies such as substrates and the transistor materials for flexible display will be introduced.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.219-220
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• 2014

Organic Light Emitting Diodes (OLED) 나 Organic Photovoltaics (OPV)와 같은 유기소자에 투명전극으로 쓰이고 있는 Indium Tin Oxide (ITO)는 유연한 소자에 적용하기에는 유연성이 떨어진다는 문제가 있다. 이를 해결하기 위해서 CNT, Graphene, AgNW, 전도성 고분자 등의 투명전극에 관한 연구가 활발히 진행되고 있으나, 여전히 전기적 특성이 좋지 못하다는 문제가 있다. 이러한 문제를 해결하기 위해서 본 연구에서는 금속배선을 보조전극으로 형성하여 배선을 폴리머 기판에 함몰시킴으로써 유연성과 표면 평탄도, 전기적 특성이 우수한 배선함몰 투명전극을 형성하였다. 그 결과, $1{\Omega}/{\Box}$의 면저항과 90%의 투과도를 가지는 투명전극을 구현하였다. 이렇게 제작된 배선함몰 전극위에 유기태양전지와 유기발광 다이오드를 제작하여 상용화된 ITO 유리기판과 유사한 효율을 얻을 수 있었다.

• ETRI Journal
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• v.31 no.6
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• pp.642-646
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• 2009

Highly efficient white phosphorescent organic light-emitting diodes with a mixed-host structure are developed and the device characteristics are studied. The introduction of a hole-transport-type host (N, N'-dicarbazolyl-3-3-benzen (mCP)) into an electron-transport-type host (m-bis-(triphenylsilyl)benzene (UGH3)) as a mixed-host emissive layer effectively achieves higher current density and lower driving voltage. The peak external quantum and power efficiency with the mixed-host structure improve up to 18.9% and 40.9 lm/W, respectively. Moreover, this mixed-host structure device shows over 30% enhanced performance compared with a single-host structure device at a luminance of 10,000 $cd/m^2$ without any change in the electroluminescence spectra.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.543-544
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• 2006

Pentacene thin film transistors fabricated without photolithographic patterning were fabricated on the plastic substrates. Both the organic/inorganic thin films and metallic electrode were patterned by shifting the position of the shadow mask which accompanies the substrate throughout the deposition process. By using an optically transparent zirconium oxide ($ZrO_2$) as a gate insulator and octadecyltrimethoxysilane (OTMS) as an organic molecule for self-assembled monolayer (SAM) to increase the adhesion between the plastic substrate and gate insulator and the mobility with surface treatment, high-performance transistor with field effect mobility $.66\;cm^2$/V s and $I_{on}/I_{off}$>$10^5$ was formed on the plastic substrate. This technique will be applicable to all structure deposited at low temperature and suitable for an easy process for flexible display.