• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1030-1033
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• 2006

The efficiency stabilization and the color coordinates in blue organic light-emitting devices (OLEDs) with a double emitting layer (DEL) consisting of 4,4'-Bis(carbazol-9-yl)biphenyl (CBP) and 4,4'-Bis(2,2-diphenyl-ethen-1-yl)diphenyl were investigated. The efficiency of the OLEDs with a DEL did not significantly change with an increase in current density. The Commission Internationale de l'Eclairage coordinates of the OLEDs with a DEL 11 V were (0.150, 0.137), indicative of a deep blue color.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.537-539
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• 2009

We report the improvement in adhesion of IZO thin films through oxygen ($O_2$) plasma treatment of organic polymer film. In conclusion, the $O_2$ plasma treatment of an organic polymer film was accomplished with improving ca. 1.8 times in adhesion than that of the only general etch treatment on the same organic polymer film.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.79-80
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• 2007

A high performance organic phototransistor with dynamic range of 120 dB is demonstrated by employing soluble pentacene as a photo-sensing layer. The organic phototransistor used suspended source/drain (SSD) electrode structure, which provides a dark current level of ${\sim}10^{-14}$ A at positive gate bias. Under a steady-state illumination, the organic phototransistor exhibited a current modulation of $10^6$ compared to dark to give a dynamic range of 120 dB. These results suggest that the organic phototransistor based on TIPS pentacene can be a new premising candidate for low-cost and high-performance photo-sensing element for digital imaging applications.

• Journal of Information Display
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• v.10 no.2
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• pp.54-61
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• 2009

The results of the optimization of the organic passivation process for fabricating thin-film transistors (TFTs) with a high aperture ratio on a seventh-generation glass (2200${\times}$1870 mm) substrate for LCD-TV panels are reported herein. The optimization of the organic passivation process has been verified by checking various factors, including the material properties (e.g., thickness, stain, etching, thermal reflow) and the effects on the TFT operation (e.g., gate/data line delay and display-driving properties). The two main factors influencing the organic passivation process are the optimization of the final thickness of the organic passivation layer, and the gate electrode. In conclusion, the minimum possible final thickness was found to be $2.42{\um}m$ via simulation and pilot testing, using the full-factorial design. The optimization of the organic passivation layer was accomplished by improving its brightness by over 10 cd/$m^2$ (ca. 2% luminance) compared to that of the conventional organic passivation process. The results of this research also help reduce the reddish stain on display panels.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.632-632
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• 2013

We generated single-crystal organic nanowire arrays using a direct printing method (liquidbridge- mediated nanotransfer molding) that enables the simultaneous synthesis, alignment and patterning of nanowires from molecular ink solutions. Using this method, single-crystal organic nanowires can easily be synthesized by self-assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly transferred to specific positions on substrates to generate nanowire arrays by a direct printing process. The position of the nanowires on complex structures is easy to adjust, because the mold is movable on the substrates before the polar liquid layer, which acts as an adhesive lubricant, is dried. Repeated application of the direct printing process can be used to produce organic nanowire-integrated electronics with twoor three-dimensional complex structures on large-area flexible substrates. This efficient manufacturing method is used to fabricate all-organic nanowire field-effect transistors that are integrated into device arrays and inverters on flexible plastic substrates.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.431-433
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• 2009

We developed 4.8 inch WQVGA e-paper on plastic substrate using organic field effect transistors (OFETs). Polyethylene naphthalate (PEN) film was used as a flexible substrate and arrays of OFETs with bottom-gate, bottom-contact structure were fabricated on it. Lowtemperature curable organic gate insulating materials were employed and polymer semiconductor solutions were ink-jetted on arrays with high-resolution. At all steps, process temperature was limited below $130^{\circ}C$. Finally, we could drive flexible e-paper displays based on OFET arrays with the resolution of 100 dpi.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.1-5
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• 2009

In this study, we have shown the power conversion efficiency of organic thin film photovoltaic devices utilizing a conjugated polymer/fullerene bulk-hetero junction structure. We use MDMO-PPV(Poly[2-methoxy-5-(3,7-dimethyloctyloxy -1,4-phenylenevinylene) as an electron donor, PCBM([6,6]-Phenyl C61 butyric acid methyl ester) as an electron accepter, and PEDOT:PSS used as a HTL(Hole Transport Layer). We have fabricated OPV(Organic Photovoltaic) devices as a function of the MDMO-PPV/PCBM concentration from 1:1 to 1:5. The electrical characteristics of the fabricated devices were investigated by means of I-V, P-V, F·F(Fill Factor) and PCE(power conversion efficiency). The power conversion efficiency was gradually increased until 1:4 ratio, also the highest efficiency of 0.4996% was obtained at the ratio.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.13-18
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• 2005

In this paper, we fabricated a pixel array in which each pixel was consisted of Organic Thin Film Transistor (OTFT) serially connected with Organic Light Emitting Diode (OLED) on Poly-ethylene-terephthalate (PET) substrate and the number of pixels was 64 x 64. As a gate insulator of OTFT, the thermally cross-linked PVP was used and the organic semiconductor, Pentacene, is deposited for an active layer of OTFT considering the compatibility with PET substrate. The mobility of OTFT is $1.0\;cm^2/V{\cdot}sec$ as a discrete device, but it was reduced to $0.1\~0.2\;cm^2/V{\codt}sec$ in the array. We analyzed the operation of the array and confirmed the current driving ability of OTFTs for the OLEDs.

• Nano
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• v.13 no.12
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• pp.1850146.1-1850146.9
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• 2018

The rapid development of smart textiles requires the large-scale fabrication of conductive fibers. In this study, we develop a simple, scalable and low-cost capillary-driven self-assembly method to prepare conductive fibers with uniform morphology, high conductivity and good mechanical strength. Fiber-shaped flexible and stretchable conductors are obtained by coating highly conductive and flexible silver nanowires (Ag NWs) on the surfaces of yarn and PDMS fibers through evaporation-induced flow and capillary-driven self-assembly, which is proven by the in situ optical microscopic observation. The density of Ag NWs and linear resistance of the conductive fibers could be regulated by tuning the assembly cycles. A linear resistance of $1.4{\Omega}/cm$ could be achieved for the Ag NWs-coated nylon, which increases only 8% after 200 bending cycle, demonstrating high flexibility and mechanical stability. The flexible and stretchable conductive fibers have great potential for the application in wearable devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1803-1804
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• 2006

In this paper, device performances of organic lightemitting diodes (OLEDs) will be presented for AMOLED and general illumination applications. Various types of advanced devices were developed to enhance the power efficacy and luminous efficiency. Here we also demonstrated longer lifetime AM-OLED structures, which lifetime is about 100 hours until $L/L_0$ reaches 0.99.