• Journal of the Korean institute of surface engineering
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• v.40 no.2
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• pp.77-81
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• 2007

To investigate the characteristics of green light-emitting OLED device, C545T material with $Alq_3$ was doped in the OLED device of $ITO(1500)/2-TNATA(400{\AA})/NPB(80{\AA})/Alq_3:C545T(160{\AA})/Alq_3(240{\AA})/LiF(3{\AA})/Al(2400{\AA})$ structure, which was used as a activator at the respective concentration of 0.5 vol.%, 1 vol.%, 2 vol.% and 3 vol.%. It was observed from the experiments that the device efficiency firstly increased with the increase of C545T concentration and the maximum efficiency of 10.9 cd/A and 4.28 lm/W was obtained at C545T concentration of 1 vol.%, and then the device efficiency decreased as the C545T activator concentration increased above 2 vol.% contents, while the longest lifetime of over 750 hours was obtained at C545T concentration of 1 vol.%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.269-270
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• 2005

A hybrid passivation method using parylene and silicon dioxide combination layer for a flexible organic light emitting diode (FOLED) was applied on a polycarbonate substrate. A parylene coating by vapor polymerization method is a highly effective passivation process for the FOLED, and it applies all top surface and the edges of the FOLED device. In order to minimize the permeation of moisture and oxygen from the top surface of the device, an additional layer of silicon dioxide was deposited over the parylene coated layer. It was found that the water vapor transmittance rate (WVTR) of parylene (15 m-in-thickness) / SiO2 (0.3$\mu$m-in-thickness) combination layers deposited on polycarbonate film was decreased under the value of 10-3 g/m2day. The FOLED with the hybrid passivation showed remarkably longer lifetime characteristics in the ambient conditions than the non-passivated FOLED. The lifetime of the passivated FOLED was 400 hours and it was more than ten times over the lifetime of the convectional non-passivated FOLED.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.495-498
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• 2012

In this paper, the basic behavior of the environment and the driving time as a prediction of the lifetime of the power semiconductor devices were recorded. Radiator of a power device driving time and temperature operating environment, including cumulative record by the controller of the power converter, and doing it so you can see the power semiconductor devices for the life of the structure that the size of the change in the temperature of the semiconductor chip and the number of iterations to maintenance warranty period because of a lifetime by forecasting or replacement can be made at the appropriate time that is considered.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.46-48
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• 2004

A micro-scale discharge device has been fabricated using MEMS technology and failure mechanisms during DC discharge are investigated for the microstructure. The failure of sustaining the plasma is mainly caused by either open or short of the micro-electrodes, both resulting from the sputtered metal atoms during the DC discharge. The glow discharge lifetime of the microstructures is found to depend on bias circuit scheme as well as the electrode structure. Based on the understanding of the failure mechanism, a novel microstructure is suggested to improve discharge lifetime and the longer lifetime is experimentally demonstrated. In addition to the failure mechanism, an electric breakdown between two electrodes with microns gap are studied using micromachined metal structures. The electrode gap is able to be accurately controlled by thickness of a sacrificial layer and the electric breakdown was measured while varying the gap from $2{\mu}m$ to $20{\mu}m$. The electric breakdown behavior was found to highly depend on the electrode material, which was not considered in Paschen's law.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1001-1004
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• 2008

An advanced backplane circuit technology for AMOLED using amorphous silicon TFTs with commercial level reliability, uniformity and lifetime was recently integrated into a prototype device. Differential aging of T98>100 hrs at 200 cd/m2 brightness and >10,000hrs lifetime is demonstrated. A 2.2" QVGA ($240{\times}320$) prototype has been developed and shown having the above-mentioned high performance.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1805-1808
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• 2006

In this paper, we describe a versatile use of fullerene(C60) as a charge transporting material for organic light-emitting diodes. The use of fullerene as a buffer layer for an anode, a doping material for hole transport layer, and an electron transport layer was investigated. Fullerene improved the hole injection from an anode to a hole transport layer by lowering the interfacial energy barrier and enhanced the lifetime of the device as a doping material for a hole transport layer. In addition, it was also effective as an electron transporting material to get low driving voltage in the device.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1411-1414
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• 2007

We have developed a top-emitting white organic electroluminescent device (TWOLED) incorporating a low-reflectivity molybdenum (Mo) anode and doped transport layers as well as a dual-layer architecture of doped blue and yellow emitters with the same blue host. The EL efficiency and operational lifetime of TWOLED can be enhanced by a factor of 1.2 and 3.4 than that of standard TWOLED, respectively, with a co-doping technology in yellow emitter by doping another blue dopant. The enhancement in device performances can be attributed to improve the energy transfer efficiency from blue host to yellow dopant through a blue dopant as medium in yellow emitter.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.925-927
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• 2008

In order to improve the performance in green phosphorescent OLED devices, Merck has developed novel host and electron blocking materials. The newly developed host materials improve the device lifetime by a factor of 3. The newly developed electron blocking materials having not only electron but also exciton barrier properties increase the efficiency of the device by a factor of 1.4. Comparable results were achieved in phosphorescent red systems with further host materials.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1692-1696
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• 2006

Dopant and host molecules for charge transport layer in OLED have been developed. They enable implementation of the PIN OLED technology in mass production. We review the status of PIN OLED with main focus on top-emission structures and operation stability at elevated temperatures. A green phosphorescent top-emission device with 2.5 V operating voltage and 90 lm/W at 1000 $cd/m^2$ is presented. For a red top-emission device, lifetime exceeding 100,000 h at 500 $cd/m^2$ initial brightness is reported. Operational stability at $80^{\circ}C$ has been investigated. A lifetime of 17,000 h at 500 $cd/m^2$ has been achieved. Finally, we comment on further reduction of the operating voltage in OLED.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.771-774
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• 2009

The Improved stability of organic light emitting diodes (OLEDs) containing lithium-quinolate (Liq) as the ETL doping material is investigated. The lifetime could be improved by threefold using the Liq-doped ETL structure. The improvement was attributed to the Liq-doped ETL, which improved hole-electron balance and has a good electrical stability. Additionally, when the Liq doped device was combined with an Mg/Al cathode, the OLED produced a longer lifetime than other device.