• Transactions on Electrical and Electronic Materials
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• v.15 no.1
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• pp.41-44
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• 2014

Emission properties of the organic light-emitting diodes were investigated with the use of a hole-injection layer of copper(II)-phthalocyanine (CuPc). The manufactured device structure is indium-tin-oxide (ITO) (180 nm)/CuPc (0~50 nm)/N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) (40 nm)/tris-(8-hydroxyquinoline) aluminum (III) ($Alq_3$) (60 nm)/Al(100 nm). We investigated the luminescence properties of $Alq_3$ which is affected by the CuPc hole-injection layer. Also, we studied the influence of light-emission properties in the structure of an ITO/CuPc/TPD/$Alq_3$/Al device depending on the several thicknesses of CuPc (0~50 nm) layer. As a result, it was found that the hole injection occurs smoothly in the device with 20 nm thick CuPc layer, and the properties become significantly worse in the device with a CuPc layer thickness higher than 40 nm. We studied the topography and external quantum efficiency depending on the layer thickness of CuPc. Also, we analyzed the electroluminescent characteristics in the low and high-voltage range.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1800-1802
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• 1999

Electroluminescence is occurred when phosphor is located in electric field. In this paper, we made powder electroluminescent device (PELD) with structured ITO film/phosphor/Insulator/silver paste. The transparent electrode was ITO film and green(2704-01) and orange(2702-02) and blue-green(2703-01) were used as phosphor. The insulator was $BaTiO_3$ and $Y_2O_3$, back electrode was silver paste. To investigate electrical and optical properties of PELDs, EL spectrum, Brightness, Transferred charge density using Sawyer-Towers circuit was measured.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.265-268
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• 2004

We have developed a highly efficient and stable blue organic electroluminescent device (OLED) based on the blue fluorescent p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-Ph) dopant in a morphologically stable high-bandgap host material, 2-methyl-9,10-di(2-naphthyl)anthracene (MADN), which achieved an EL efficiency of 9.7 cd/A and 5.5 lm/W at 20 mA/$cm^2$ and 5.7 V with a Commission Internationale d'Eclairage coordinates of(x = 0.16, y = 0.32). This sky blue device which could also alleviate the problematic current induced quenching at high current achieved a half-decay lifetime ($t_{1\;2}$) of 46,000 h at an initial brightness of 100 cd/$m^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.351-354
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• 2001

We fabricated organic electroluminescent(EL) devices with mixed emitting layer of poly (N- vinylcarbazole) ( PVK) , 2,5-bis (5-tert-butyl -2- benzoxaBoly) thiophene ( BBOT) , N,N-diphenyl-N,N- (3-methyphenyl) -1,1-biphenyl-4, 4-thiamine(TPD) and poly(3-hexylthiophene) (P3HT) deposited by LB(Langumuir-Boldgett) method. From the AFM(atomic force microscope) images, the monolayer containing 30% of AA(arachidic acid) showed a roughness value of 28$\AA$. In the voltage-current characteristics of ITO/Emitting layer/BBOT/LiF/A1 devices, current density much smaller than that of the spin-coated devices having a same thickness.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.928-931
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• 2003

In order to realize full color display, two approaches were used. The first method is the patterning of red, green, and blue emitters using a selective deposition. Another approach is based on a white-emitting diode, from which the three primary colors could be obtained by micro-patterned color filters. White-light-emitting organic light emitting devices (OLEDs) are attracting much attention recently due to potential applications such as backlights in liquid crystal displays (LCDs) or other illumination purposes. In order for the white OLEDs to be used as backlights in LCDs, the light emission should be bright and have Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.33, 0.33). For obtaining white emission from OLEDs, different colours should be mixed with proper balances even though there are a few different methods for mixing colors. In this study, we will report a white organic electroluminescent device using exciton diffusion length concept.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.269-272
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• 2000

In this paper, we was fabricated and analyzed a blue organic electroluminescent devices with the organic dye, such as 1,1,4,4-Tetraphenyl-1,3-butadi-ene(TPB). The device was made by simultaneously co-depositing two materials. The device structure was composed of the ITO glass, TPD, Alq$_3$doped TPB, and aluminum(A1) electrode. Carrier injection from the two electrodes was significant]y observed and the blue light in EL spectrum, with an emission maximum at 462nm, was triggered at a driving voltage of 11V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.111-114
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• 2003

Compared to a conventional atomic layer deposition (ALD) grown Al203 film, Plasma enhanced ALD (PEALD) grown AION film was revealed to possess a large breakdown field, which is necessary for stable operation of thin film electroluminescent (TFEL) device. Also, AION is more stable than Al203 films grown by PEALD or by ALD after post-annealing process, which is inevitably required to improve luminance property of phosphor. Furthermore, AION films were applied to insulators of ZnS:Tb TFEL device. Resultant1y, they show better stability than ALD grown insulators under high electric field.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.37-38
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• 2000

The ZnS:Tb thin-film electroluminescent devices were grown by atomic layer deposition with utilizing single-layer aluminum oxide and/or multilayered tantalum aluminum oxide, $Ta_xAl_yO$, as upper and lower insulating layers. These devices were investigated in terms of the luminescent and electrical characteristics. From this analysis, the devices using the $Ta_xAl_yO$ instead of $Al_2O_3$ were observed to have a lower threshold voltage for emission due to the higher relative dielectric constant of $Ta_xAl_yO$ insulators than that of the $Al_2O_3$ device. And there was a large amount of dynamic space charge generation in the phosphor of the device with the $Ta_xAl_yO$ insulators seemingly due to electron multiplication such as trap ionization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.121-124
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• 1998

Generally the structure of powder electroluminescent devices (PELDs) on ITO-film was makeup of the ZnS:Cu phosphor layer and BaTiO$_3$ insulating layer. The active layer, which consists of a suitably doped ZnS powder mixed in a dielectric, is sandwiched between two electrodes; one of which are ITO film and the other is aluminum. In this paper, three kinds of powder eleotroluminescent devices (PELDs) : WK-A(ITO/BaTiO$_3$/ZnS:Cu/Silver paste). WK-B(ITO/BaTiO$_3$+ZnS:Cu/Silver paste) and WK-C(ITO/BaTiO$_3$/ZnS:Cu/BaTiO$_3$/Silver paste), fabricated by spin coating method, were investigated. To evaluate the luminescence properties of three kinds of PELDs, EL emission spectroscopy, transferred charge density and time response of EL emission intensity under square wave voltage driving were measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.286-290
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• 1999

Electroluminescence is occurred when phosphor is located in electric field. In this paper, we made powder electroluminescent device (PELD) with structured ITO film/Phosphor/Insulator/Silver paste. The transparent electrode was ITO film and green(2704-01), orange(2702-02) and blue-green(2703-01) were used as phosphor. The insulator was BaTiO$_3$ and $Y_2$O$_3$, back electrode was silver paste. To investigate electrical and optical properties of PELDs, EL spectrum, Brightness, Transferred charge density using Sawyer-Tower\`s circuit was measured.