• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1410-1412
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• 2005

We present that the electroluminescence (EL) efficiency can be improved by doping an electron transport layer (ETL) with organic materials which can make electron current increase. The electron transport layer of aluminum tris(8 -hydroxyquinoline) (Alq3) is doped with 2-(4-Biphenylyl)-5-(4-tertbutylphenyl)- 1,3,4-oxadiazole) (butyl-PBD) to enhance the electron mobility of the ETL. The higher quantum efficiency of device having ETL using Alq3 doped with butyl-PBD can be attributed to the improved electron and hole balance.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.103-106
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• 1999

Organic electroluminescent devices (OELDs) have received a great deal of attention due to their potential application as full-color displays. Europium complexes are known as excellent red light-emitting materials for OELDs since they show intense photoluminescence at around 612 nm with a narrow spectral bandwidth. In this study, a novel curopium complex, Eu(TTA)$_3$(TPPO) was synthcsizcd and its photoluminescent and electroluminescent characteristics were investigated with a device structure of ITO/TPD/Eu(TTA)3(TPPO)/A1q$_{3}$ Al, where sharp emission at the wavelength of 615 nm has been observed. Details on the electrical properties of these structures will be also discussed.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.448-452
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• 2005

This study was based on organic electroluminescence display. Especially, TPD and $\alpha-NPD$ for the hole transport materials were synthesized by Ullmann reaction. This reaction was conducted between 3­methylphenylamine, 1-naphthylamine and 4,4'-diiodobiphenyl in toluene containing CuCl catalyst and KOH base. The structural property of reaction products were analyzed by FT-IR, $^1H-NMR$ spectroscopy, and thermal stability, reactivity and PL property were analyzed by melting point, yield and emission spectrum, respectively. The photoluminescence spectra of a pure TPD and $\alpha-NPD$ were observed at approximately 416nm and 438nm respectively. In this study, it was known that the melting point, yield, PL properties of TPD and $\alpha-NPD$ were changed by substituent group of amines.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.182-183
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• 2012

Organic light emitting diode (OLED) 나 organic photovoltaic device (OPV)와 같은 유기소자에 전극으로 쓰이고 있는 indium tin oxide (ITO) 박막의 품질을 향상시키기 위해 수소 및 산소의 가스량을 조절하면서 rf power를 이용하여 ITO 박막을 증착한 후 전기적, 광학적 특성을 관찰하여 보았다. 또한 ITO 박막의 대면적화 및 양산화를 위하여 Roll to Roll 장비를 적용하였다. 산소 분율 0.3%에서 두께 180 nm 와 면저항 21 ohm/sq.를 나타냈으며 수소 분율 0.8%에서 두께 180 nm, 면저항 22 ohm/sq.이 관찰되었다. 또한 산소 분율 0.3%로 고정한 후 수소 분율을 변화시키며 관찰한 결과 수소분율 0.3%에서 두께 180 nm, 면저항 19 ohm/sq.를 나타내었다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.562-567
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• 2017

The organic light-emitting diodes are fabricated with six anthracene derivatives containing simple substituents such as phenyl or naphthyl group. The device structure is as in the following: Indium tin oxide (ITO) (180 nm)/4,4-4,4',4"-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (2-TNATA) (30 nm)/4,4'-bis[N-(1-naphthyl)-N-phenyl-1-amino] biphenyl (NPB) (20 nm)/Emitting compound (30 nm)/2,2',2"-(1,3,5-Benzinetriyl)-tris (1-phenyl-1-H-benz-imidazole) TPBi (40 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). In the emitting layer the anthracene derivatives are used without any dopant. All the six devices show blue emissions. Among the tested diodes, the one with 9-(2-naphthyl)-10-(p-tolyl) anthracene (2-NTA) exhibited luminous efficiency, power and external quantum efficiencies of 3.26 cd/A, 0.98 lm/A, 2.8 % at $20mA/cm^2$.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.780-783
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• 2002

We report very efficient white OLEDs consisting of a blue-emitting 4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}$-NPD), a hole-blocking layer of 2,9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) doped with red fluorescent dye of 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro- 1H, 5H-benzo[i,j]quinolizin-8-yl) vinyl]-4H-pyran) (DCM2), and green-emitting tris(8-hydroxyquinoline) aluminum ($Alq_3$). The device with the structure of ITO/${\alpha}$-NPD (50 nm)/BCP:DCM2 (0.8 %, 4 nm)/$Alq_3$ (50 nm)/LiF (0.5 nm)/Al shows a white emission with the CIE coordinates (0.329, 0.333). The maximum luminance of 20,800 cd/$m^2$ is obtained at 15.4 V. The power efficiency is 2.6lm/W and the external quantum efficiency is 2.1 % at a luminance of 100 cd/$m^2$ at the bias voltage of 6 V.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1890-1892
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• 2005

Recently, high luminance and high efficiency were realized in OLEDs with multilayer structure including emitting materials such as metal-chelate complexes. New luminescent materials, [2- (2-hydroxyphenyl)-quinoline] (Zn(HPB)q), [(1,10-phenanthroline)- (8-hydroxyquinoline)] Zn(Phen)q was synthesized. Zn-Complexes have low molecular compound and thermal stability. The ionization potential(IP) and electron affinity(EA) of Zn-complexes were measured by cyclic-voltammetry(CV). The fundamental structure of the OLEDs was $ITO/{\alpha}$-NPD/Zn-Complex/Al and then we made device structure rightly in energy band gap. We using Zn(Phen)q as emitting layer and Zn(HPB)q as electron transport layer. We measured current density-voltage, luminance-voltage characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.8
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• pp.664-668
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• 2011

In this study, we have fabricated the red OLED (organic light emitting diode). The basic device structure is ITO/hole transporting layer, TPD(500 $\AA$)/red emitting layer, Alq3 doped with DCM2:rubrene(20 $\AA$)/electron transporting layer, Alq3(M) (500 $\AA$-M $\AA$)/LiF(15 $\AA$)/Al(1,000 $\AA$). The thickness of electron transporting layer(500 $\AA$-M $\AA$) changed 0, 20, 40, 60 $\AA$. Turn on voltage of the red OLED was 5 V, 6 V, 6.5 V and 7.5 V, respectively with electron transfer layer changed ratio. Luminance of red OLED was 4,504, 1,840, 1,490 and 1,130 cd/$m^2$, respectively. Optimized electron transfer layer position changed ratio of the red OLED was 0 $\AA$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.447-450
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• 2003

In this paper, new luminescent material, 6,11-dihydoxy-5,12-naphtacene-dione Alq3 complex (Alq2-Ncd), 1,4-dihydoxy-5,8-naphtaquinone Alq3 complex(Alq2-Nq) was synthesized. And extended efforts had been made to obtain high-performance electroluminescent(EL) devices, since the first report of organic light-emitting diodes(OLEDS) based on tris-(8-hydroxyquinoline) aluminum(Alq3). We have performed investigate characterization of the materials. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured by Flat Panel Display Analysis System(Model 200-AT) at room temperature. An intensive research is going on to improve the device efficiency using the hole injection layer, different electrodes, and etc. By using the hole injection layer, the charge-injection can be controlled and the stability could be improved. This study indicates not only the sterical effect but also some other effects would be responsible for the change of the emission wavelength.