• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.914-916
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• 2003

Novel red organic electroluminescent (EL) dye, RED was developed for an application to the emission layer of EL device. Well known red material DCJTB was also used for comparison. Two kinds of devices were fablicated; one is ITO/ CuPc / TPD / 0.5% RED-1 in Alq3/ Alq3/ Li20/ Al and the other is ITO/ CuPc /TPD / 0.5% DCJTB in Alq3/Alq3/ Li20 / Al. External quantum efficiency of the EL device with RED was two times higher than that of the device with DCJTB. The maximum EL peak was detected at 635nm in the RED EL device.

• Transactions on Electrical and Electronic Materials
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• 제15권1호
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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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1034-1037
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• 2006

We have developed a novel thin film encapsulation method for thin-cathode OLED by introducing organic (not polymer)/inorganic multiple thin films to protect device, which is shown to slow down the permeation rate of moisture and oxygen. From the stability test of devices, the projected lifetime of thin-cathode OLED device with thin film encapsulation was similarly to that with glass lid encapsulation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.265-268
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• 2000

Organic electroluminescent(EL) devices have been expected to be useful in novel-type flat-panel displays. This paper has fabricated and analyzed a red organic EL device with the use of organic dyes, such as DCMI and Nile Red. In this paper, the light emitting layer consists of tris-(8-hydroxyquiniline) aluminum(Alq$_3$) doped with organic dyes.

• 폴리머
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• 제24권1호
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• pp.90-96
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• 2000

고분자 정공 전달체로 LB 기법에 의해 제조한 PDPMA 초박막과 발광층으로 Alq$_3$를 사용하여 유기 발광소자를 제작하였다. 표면활성제로 arachidic acid를 사용하여 안정한 PDPMA 단분자막을 얻을 수 있었다. PDPMA LB 필름의 두께와 320nm의 최대 흡광도는 층수의 증가에 따라 거의 선형적으로 증가하였다. ITO/PDPMA LB 필름(19층)/Alq$_3$/Al으로 구성된 유기 적층형 소자는 DC 14V에서 2500 cd/m$^2$의 높은 휘도를 갖는 녹색 빛을 발광하였다. 특히 PDPMA LB 필름의 층이 15로 이루어진 발광소자의 구동전압은 4V의 매우 낮은 값을 나타내었다. PDPMA LB 필름의 두께 조절 및 분자 배향에 따른 EL 성능에 미치는 영향에 관하여도 검토하였다.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권2호
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• pp.37-41
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• 2001

In this study, organic electroluminescent devices with the ITO/TPD/Alq$_3$/cathode structure, using various materials of Al, Mg:Ag, Al:Li, MgF$_2$/Al, and LiF/Al as cathodes, were fabricated. We investigated the electrical and optical properties of the devices as follow: current density-voltage(J-V), luminance-voltage(L-V) and luminous efficiency-voltage curves. The bilayer cathodes with LiF/Al and MgF$_2$/Al exhibited better device performance than the other cathodes. It is considered that the improved performance of the organic electroluminescent devices is attributable to the lowering of driving voltage caused by the enhanced electron injection. The alkaline-earth fluorides are desirable materials to improve the performance of the EL devices with the Al cathode, and high luminous efficiency was achieved.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.701-705
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• 2002

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 colors 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 based on an incomplete energy transfer. In which the blue and green emission come from the same layer via incomplete energy transfer.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.743-747
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• 2001

New azomethine metal complexes were synthesized systematically and characterized. Beryllium, magnesium, or zinc ions were used as a central metal cation and aromatic azomethines (L1-L4) were employed as a chelating anionic ligand. Emission peaks o f the complexes in both solution and solid states were observed mostly at the region of 400-500 nm in the luminescence spectra, where blue light was emitted. Three of them (BeL1 (Ⅰ), ZnL2 (Ⅱ), and ZnL3 (Ⅲ)) were sublimable and thus were applied to the organic light-emitting devices (OLED) as an emitting layer, respectively. The device including the emitting layer of Ⅰ exhibited white emission with the broad luminescence spectral range. The device with the emitting layer of Ⅱ showed blue luminescence with the maximum emission peak at 460 nm. Their ionization potentials, electron affinities, and electrochemical band gaps were investigated with cyclic voltammetry. The electrochemical gaps of 2.98 for I, 2.70 for Ⅱ, and 2.63 eV for Ⅲ were found to be consistent with their respective optical band gaps of 3.01, 2.95 and 2.61 eV within an experimental error. The structure of OLED manufactured in this study reveals that these complexes can work as electron transporting materials as well.

• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.757-761
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• 2001

We studied emitting properties of organic electroluminescent devices fabricated using the spin-coating and Langmuir-Blodgett(LB) technique. The LB technique has the advantage of precise control of the thickness better than spin-coating method. LB monolayer of poly(3-hexylthiophene)(P3HT) was deposited 27 layers onto the indium-tin-oxide(ITO) substrate as Y-type films by the vertical dipping method. In the absorption spectra, the λ$\_$max/ of P3HT-AA LB films and of spin-coating films showed about at 510, 545 and 590 nm corresponding to 2.43, 2.28, 2.10eV. And we observed that the turn-on voltage of devices deposited by LB method(10V) was higher than that of spin-coating method(8.5V) in voltage-current-luminance characteristic. In the logV-logJ characteristics of ITO/P3HT-AA LB/Al device, we confirmed that El device fabricated by LB method follows three conduction mechanisms: ohmic, space-charge-limited current(SCLC) conduction and trapped-carrier-limited space-charge current(TCLC) conduction.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 학술대회 및 기술세미나 논문집 디스플레이 광소자
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• pp.81-82
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• 2006

Doping is a well-known method for improving electroluminescent (EL) efficiency of organic light emitting diodes. In our study, doping with 2 materials simultaneously, we could achieve improved EL efficiency. The emission layer was tris-(8-hydroxyquinoline)aluminum, and the 2 dopants were N,N'-dimethyl-quinacridone (DMQA) and 10-(2-Benzothiazolyl)-2, 3, 6, 7-tetrahydro-1,1,7,7,-tetramethyl 1-1H, 5H, 11H-[1] benzopyrano [6,7,8-ij]quinolizin-11-one (C-545T). The EL intensity of co-doped device was nearly flat, it shows that co-doping technique could be a effective way to improve the EL efficiency. EL efficiency of Single-doped device based on DMQA and C-S45T were ~6.47Cd/A and ~7.45Cd/A, respectively. Co-doped device showed higher EL efficiency of ~8.30Cd/A.