• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1638-1641
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• 2008

We have investigated the effectiveness of a gravure printing method for the fabrication of organic light-emitting diode (OLED) and Organic Thin Film Transistor (OTFT). Printing of the organic layers was performed with a small-scale gravure coating machine, while the metallic layers were vacuum-evaporated. Devices with gravure-printed layers are at least comparable with the spin-coated devices. Effects of the solvent formulation and surface energy mismatch between the organic layer materials on the printed patterns and device performance were discussed. We will present the initial design and experimental data of OTFT fabricated by roll-type soft contact transfer process.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.707-710
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• 2004

We have proposed on dual-drive & -emission (DDE) panel based on organic light-emitting diodes (OLEDs). The device is composed on independent operation of two OLED structures with two transparent electrodes for data signals and an intermediate reflective electrode for common scan signal. Typical device structure is ITO / organic electroluminescent layer (1) /intermediate reflective electrode / organic electroluminescent layer (2) /transparent electrode. Symmetric bright emission could be obtained by applying AlNd as the intermediate reflective electrode and $MoO_3$ as a hole injection layer for upper device structure. The proposed panel is useful for emissive face-to-face panel exhibited for different images.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.563-567
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• 2006

Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.

• Korean Journal of Materials Research
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• v.32 no.7
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• pp.320-325
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• 2022

Single OLED and tandem OLED was manufactured to analyze the electroluminescence characteristics of DC driving, AC driving, and full-wave rectification driving. The threshold voltage of OLED was the highest in DC driving, and the lowest in full-wave rectification driving due to an improvement of current injection characteristics. The luminance at a driving voltage lower than 10.5 V (8,534 cd/m²) of single OLED and 20 V (7,377 cd/m²) of a tandem OLED showed that the full-wave rectification drive is higher than that of DC drive. The luminous efficiency of OLED is higher in full-wave rectification driving than in DC driving at low voltage, but decrease at high voltage. The full-wave rectification power source may obtain higher current density, higher luminance, and higher current efficiency than the AC power source. In addition, it was confirmed that the characteristics of AC driving and full-wave rectification driving can be predicted from DC driving characteristics by comparing the measured values and calculated values of AC driving and full-wave rectification driving emission characteristics. From the above results, it can be seen that OLED lighting with improved electroluminescence characteristics compared to DC driving is possible using full-wave rectification driving and tandem OLED.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.1014-1018
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• 2007

We have demonstrated the enhancement of the power efficiency and device lifetime of organic light-emitting diodes (OLEDs) by introducing the ETL 1 / ETL2 (composite ETL) structure between EML and cathode and the HIL1 (composite HIL) / HIL2 between anode and HTL. Compared to reference devices retaining conventional architecture, novel OLED structure shows an outstanding EL efficiency that is 1.6 times higher (${\sim}4.5$ lm/w versus ${\sim}$ 2.71 lm/w for the reference device) and lower driving voltage $({\bigtriangleup}V>1V)$, but also a longer lifetime and smaller operating voltage drift over time. It is suggested in this work that the device performance can be improved by in-situ ohmic contact through novel electron controlled structure and reduction of charge accumulation in the interface through composite HIL

• Journal of the Semiconductor & Display Technology
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• v.11 no.1
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• pp.49-54
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• 2012

There have been plenty of difficulties because properties of Alq3 are unable to acquire in a process of manufacture of OLED. In this paper it will predict a viscosity of Alq3 through DSMC technique and suggest the way regarding a study to estimate properties of material through the computer simulation. There could generate errors of a simulation process in a vacuum deposition process since the properties of material that is used in a high-degree vacuum environment are not secured. Therefore, we would like to propose the new methods that can not only predict properties of a molecular unit but also raise an accuracy of simulation process by forecasting properties of Alq3.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.2
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• pp.104-109
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• 2014

To operate organic light emitting device (OLED) with alternating current (AC) power source without AC/DC(direct current) converter, we fabricated the fluorescent OLED and measured the emission characteristics with AC and DC. The OLED operated by AC showed higher maximum current efficiency of 8.2 cd/A and maximum power efficiency of 8.3 lm/W. But current efficiency and power efficiency of AC driven OLED showed worse than DC driven OLED at high voltage above 10 V. This result can be explained by the peak voltage of AC was $\sqrt{2}$ times than DC, In case of low driving voltage the emission characteristics were improved by the peak voltage of AC, but in case of high driving voltage the emission efficiencies were decreased by the roll off phenomena. Finally, serial OLED arrays using twelve OLEDs driven by AC 110 V showed average voltage of 9.17 V, voltage uniformity of 99.0%, average luminance of $1,175cd/m^2$, luminance uniformity of 94.4%.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1570-1572
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• 2004

OLED(organic light-emitting diode)소자에 사용되는 ITO(Indium-tin oxide)전극에 Ar/$O_3$ 플라즈마 표면처리 함으로써 ITO전극에 표면상태의 개선에 좋은 영향을 미치는 것으로 나타났다. 13.56MHZ RF 플라즈마 장치를 이용하여 Ar/$O_3$ 플라즈마 처리한 후 AFM(atomic force microscopy)측정을 통해 표면 morphologyjroughless를 분석하고, XPS(X-Ray Photoelectron Spectroscopy)분석을 통해 표면의 화학적 조성비 분석을 수행 하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.793-796
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• 2005

A structure and a design of device were developed to fabricate large-scale active matrix organic light-emitting diode (AMOLED) display with good color purity and high aperture ratio. With these technologies, we developed a full color 14.1 inch WXGA AMOLED display. For the integration of OLED on an active matrix a-Si TFT backplane, an efficient top emission OLED is essential since the TFT circuitry covers a large position of the pixel aperture. These technologies will enable up the OLED applications to larger size displays such as desktop monitors and TVs.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.11-16
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• 2010

The performance of an OLED fabrication system strongly depends on the design of the evaporation cell-source. Therefore, necessity of the preceding study for cell source development of new concept is becoming increase. A development plan to substitute for experiment is applied as use simulation. In this study interpret behavior of a particle through DSMC techniques, and in this paper presenting a form to make so as to have better performance of the pointtype cell source which had a nozzle.