• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.84-87
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• 2005

본 논문에서는 p-type 고분자 물질인 P3HT (Poly-3-hexylthiophene)를 잉크젯 프린팅 방식으로 활성화층을 적층함으로써 Organic thin film transistor를 제작하여 이에 대한 특성을 연구하였다. Piezoelectric 방식의 잉크젯 프린팅을 이용하여 P3HT single drop jetting 시 두께 $150{\sim}200{\AA}$, 직경 약 70 ~ 80 um정도의 drop profile을 얻을 수 있었다. P3HT의 solvent로서 Chlorobenzene을 사용하여 농도 약 0.5 wt.%의 Ink-jet용 ink를 제작하여 이를 Channel Width 37, 236 um 크기의 Au 전극 위에 jetting 하여 각각의 특성을 측정하였다. 상기 실험은 상온의 외부환경에서 실시되었으며 실험 결과 최대 ${\mu}=1{\times}10^{-2}\;cm^2/Vsec$, $I_{on}/I_{off}=10^3{\sim}10^4$ 정도로서 off current가 높은 편이나 이동도 측면에서는 다른 방법의 박막 증착 실험결과와 비교할 때 동등 수준의 결과를 얻을 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.113.1-113.1
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• 2011

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active compo-nents in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT(Thin Film Transistor), which are printed withfunctional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manu-facturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and active layer which consist of the P3HT:PCBM. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

• Journal of the Korea Society of Computer and Information
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• v.17 no.9
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• pp.149-156
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• 2012

The Fabric Electrode was proposed for the effective production of the display based on electrowetting in this paper and designed the source driver of flexible display which could be driven by the electrowetting cell. The electrowetting cell matrix was implemented on the substrate(PET) by imprinting. The driver fabric, wetting electrode fabric and conductive fabric was placed horizontally and vertically in the groove between cell matrix and the electrowetting cell matrix can be driven by the cross-point as electric connection. The integration density of driver module is decreased because using the R/2R DAC module per channel in the conventional method. The proposed method could utilize the effective production process and reduce the production price of a display panel. The source driver which consume lower power and can increase the integration density because of reducing the number of driver device per channel was designed and evaluate the driver operation by the simulation using the VHDL programming in this paper.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.379-382
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• 2004

In this paper we fabricated a test panel for AMOLED on glass and PET substrate. The test panel consisted of the various size of OTFTs and OLEDs and the current driving capability of OTFTs for OLEDs has been investigated. OTFTs were made of the inverted staggered structure and employed polyvinylphenol (PVP) as the gate insulator and pentacene thin film as the active layer. The OTFTs produced the filed effect mobility of $0.3 cm^2/V.sec$ and on/off current ratio of $10^5$. OLEDs consisted of TPD for HTL and Alq3 for EML with 35nm thick, generating green monochrome light. We found that OTFT with channel length of 70${\mu}m$ and channel width of over 3.5mm provided the sufficient current to OLED to generate the luminescence of $0.3Cd/m^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.95-96
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• 2008

A new voltage-driven pixel circuit using soluble-processed organic thin film transistors (OTFTs) for an active matrix organic light emitting diode (AMOLED) is proposed. The proposed circuit is composed of four switching TFTs, one driving TFT and one storage capacitor. The proposed circuit can compensate for the degradation of OLED current caused by the threshold voltage shift of the OTFT. The simulation results show that the variation of OLED current corresponding to a 3V threshold voltage shift is decreased by 30% compared to the conventional 2TlC structure.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.84.2-84.2
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• 2010

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active components in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT, which are printed with functional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manufacturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem: it is difficult to apply toa continuous process as a R2R printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, anelectrostatic atomizer sprays micro-drops from the solution injected into the capillary, with electrostatic force generated by electric potential of about tens of kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and Active layer which consist of the P3HT:PCBM. The result of experiment, organic solar cell using ESD thin film coated method is occurred efficiency of about 1.4%. Also, the case of only used to ESD method in the active layer coating is occurred efficiency of about 1.86% as the applying a spin coating in the PEDOT:PSS layer. We can expect that ESD method is possible for continuous process to manufacture in the organic solar cell or OLED device.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.262-268
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• 2010

Organic light emitting diode is developed fast from 1963 after discovering electric light emitting phenomenon. First PMOLED(passive matrix OLED) product is manufactured and AMOLED(active matrix OLED) using TFT(thin film ransistor) is now in the center. PMOLED is mainly mounted at sub display. but AMOLED is mounted at main display. Also AMOLED expand the market to PMP(portable multimedia players), navigation and TV. Even thought OLED's market is opening to many applications, OLED is worried about lifetime until now. That's appeared in market in a very short time and is not known well about result of OLED's lifetime and reliability test. And there is no standard ssessment method and not enough study to standardization the method. A study's purpose is reduce the time for life test by accelerated current and it can do production possible design by accelerated life model in design phase. It's must be add to process variables and design variables(like ratio of light emitting, organic material structure, condition of aging, etc) to make the best use of supplied accelerated lifetime model in this paper. In terms of lifetime it needs each criterion of applications because of image sticking. In conclusion, it's possible to discover new defect because there is not much time to be opened in market and develop a method of manufacturing process & materials, so we need to study on the subject of this paper continuously.

• Journal of the Semiconductor & Display Technology
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• v.5 no.1 s.14
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• pp.39-43
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• 2006

The polyvinyl series organic films as gate insulators of thin film transistor(TFT) have been processed and characterized on the polyether sulphone (PES) substrates . The poly-4-vinyl phenol(PVP) and polyvinyl toluene (PVT) were used as solutes and propylene glycol monomethyl ether acetate(PGMEA) as a solvent in the formation of organic insulators. The cross-linking of organic insulators was also attempted by adding the thermosetting material, poly (melamine-co-formaldehyde) as a hardener in the compound. The electrical characteristics measured in the metal-insulator-metal (MIM) structures showed that insulating properties of PVP layers were generally superior to those of PVT layers. Among the layers of PVP series; copolymer PVP(10 wt%), 5wt% cross-linked PVP(10 wt%), copolymer PVP(20 wt%), 5 wt% cross-linked PVP(20 wt%) and 10 wt% cross-linked PVP(20 wt%), the 10 wt% cross-linked PVP(20 wt%) layer showed the lowest leakage current of 1.2 pA at ${\pm}10V$. The ms value of surface roughness and the capcitance per unit area are 2.41 and $1.76nF/cm^2$ in the case of 10 wt% cross-linked PVP(20 wt%) layer, respectively.