• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.972-975
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• 2002

Electroluminescence(EL) devices based on organic thin layers have attracted lot of interests because of their application as display. One of the problems is red material. It offered a short life and poor emission efficiency to boot. In this study, this problem can be solved by using a multi-layer device structure. Organic electroluminescent devices which are composed of organic thin multi-layer films are fabricated. The basic structure is ITO / Emitting layer / LiP / Al EL device in which Hole transport/Electron blocking PVK layer was blending. We demonstrate the enhancement of eletroluminescence (EL) from blends of poly(3-hexylthiophene) in poly(N-vinylcarvazole). The emitting layer is consisted of a host material(PVK) and a guest emitting material(P3HT). It was showed higher EL intensity and their electro-optical properties were investigated.

• 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 Materials Research Society of Korea Conference
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• 2001.05a
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• pp.122-122
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• 2001

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.125-128
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• 1998

Electroluminescent(EL) devices based on organic thin films have attracted lots of interests in large-area light-emitting display. One of the problems of such device is a lifetime, where a degradation of the cell is possibly due to an organic layer's thickness, morphology and interface with electrode. In this study, light-emitting organic electroluminescent devices were fabricated using Alq$_3$(8-hydroxyquinolinate aluminum) and TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1-1'-biphenyl]-4,4'-diamine).Where Alq$_3$ is an electron-transport and emissive layer, TPD is a hole-transport layer. The cell structure is ITO/TPD/Alq$_3$/Al and the cell is fabricated by vacuum evaporation method. In a measurement of current-voltage characteristics, we obtained a turn-on voltage at about 9 V. And we used other buffer layer of PPy(Polypyrrole) with ITO/PPy/TPD/Alq$_3$/Al structure. We observed a surface morphology by AFM(Atomic Force Microscopy), UV/visible absorption spectrum, and PL(Photoluminescence) spectrum. We obtained the UV/visible absorption peak at 358nm in TPD and at 359nm in Alq$_3$, and at 225nm and the PL peaks at 410nm in TPD and at 510nm in Alq$_3$ and at 350nm. We also studied EL spectrum in the cell structure of ITO/TPD/Alq$_3$/Al and ITO/PPy/TPD/Alq$_3$/Al and we observed the EL spectrum peak at 510nm from our cell

• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.21-25
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• 1998

Organic-based electroluminescent devices have attracted lots of interests because of their possible application as a large-area flat panel display. Polyimides have been used for photo-alignment in LCD(Liquid Crystal Display). However, the devices used in this study were fabricated with polyimide doped with N,N'-Diphenyl-N,N'-di(m-tolyl)-benzidine(TPD) (3, 10, 30wt%) for electroluminescent hole tranforting layer(EHTL). The photochemical and physical properties of EHTL was studied. The film thicknesses were reduced under illumination with UV light. Polyimide films doped with TPD(3wt%) was irradiated and the electrical properties of the films were studied.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.944-947
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• 2003

We report efficient white organic electroluminescent devices consisting of a blue-emitting layer of 9,10-bis[(2",7"-di-t-butyl)-9',9"-spirobifluorenyl]anthracene (TBSA) and a red-emitting layer of 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[i,j]quinolizin-8-yl)vinyl]-4H-pyran) (DCM2) doped into 4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}-NPD$). The device shows the CIE coordinates of (0.32, 0.37). The external quantum efficiency is about 3.4 % and the luminous efficiency is about 3.9 lm/W at luminance of 100 $cd/m^{2}$. The maximum luminance is about 45,400 $cd/m^{2}$ at 11.5 V.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.37-40
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• 2002

We have been fabricated the white organic electroluminescent devices using vacuum evaporation method. The structure of the white OELD is Glass/1T0/NPB/DPVBi/AI $q_{3:}$ Ru bren e/B CP/Alq $q_3$/Al. We have got the white emission with two-wavelength that is mixing blue emission in DPVBi layer and orange emission in Al $q_{3:}$Rubrene layer by varying tile doping concentrations of Rubrene and the thickness of NPB layer.yer.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.443-445
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• 2000

The high mobilitie sallow larger current to be reached under operation in the space charge limited conduction region, hence facilitate access to higher luminance as required for passive matrix panel. In this work, we have investigated the molecular alignment control effect of organic electroluminescent devices. we aligned the p-sexiphenyl(6p) using a simple rubbing treatment. We studied the anisotropic optical properties and electrical characteristics.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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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.