• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.109-111
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• 2001

In this study, The cathode interface layer (CIL) was investigated using aromatic diamine derivatives. Cz-TPD (4,4'-biscarbazolyl (9)-biphenyl) used in the cathode interface layers is investigated emition charcaracteristics at the green organic electroluminescent devices TPD (N.N'-dyphenyl-N-N'-bis(3-methy phenyl)-1.1'-biphenyl-4.4'-diamine) as the hole transformer layer and $Alq_3$:tris (8-hydroxyquinoline) aluminium) as the electron transport layer and emiting layer maded use of the organic electroluminescent device. The Organic Electroluminescent Device with Ag, cathode and CIL of Cz-TPD(4,4'-biscarbazolyl(9)-biphenyl) showed good EL characteristics compare to a conventional Mg:Ag device and also an improved storage stability.[1] As the change in MgAg, Cz-TPD/Ag, Ag at the chthode, the electron and optical charcaracteriseics were investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.124-127
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• 2002

In this study, The cathode interface layer (CIL) was investigated using aromatic diamine derivatives. Cz-TPD (4,4'-biscarbazolyl(9)-biphenyl) used in the cathode interface layers is investigated emition charcaracteristics at the green organic electroluminescent devices. TPD (N,N' -dyphenyl -N -N'-bis (3-methy phenyl)-1,1' -biphenyl-4,4' -diamine) as the hole transformer layer and $Alq_{3}:tris$ (8-hyd-roxyquinoline) aluminium) as the electron transport layer and emiting layer maded use of the organic electroluminescent device. The Organic Electroluminescent Device with Ag cathode and CIL of Cz-TPD(4,4'-biscarbazolyl(9)-biphenyl) showed good EL characteristics compare to a conventional Mg:Ag device and also an improved storage stability. [1] As the change in MgAg, Cz-TPD/Ag, Ag at the chthode, the electrical and optical charcaracteriseics were investigated.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.175-195
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• 2008

Recent years have brought remarkable developments in white light emitting devices (WLEDs) and white organic light-emitting devices (WOLEDs). However, their efficiency, CIE values, CRI and lifetime are still not ideal. This review covers detailed discussion about syntheses of organometallic complexes, inorganic phosphors and quantum dots used in WLEDs, WOLEDs and their electroluminescent properties until December 2007.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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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.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.885-886
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• 2003

A bilayer is used as an anode electrode for organic electroluminescent devices. The bilayer consist of an ultrathjn ZnO layer adjacent to an hole-transporting layer and an Indium tin oxide(ITO) outerlayer. We tried to bring low the barrier between the devices as deposited ZnO films on ITO substrates. We fabricated the organic EL structure consisted of Al as cathode, $Al_{2}O_{3}$ as electro transport layer, Alq3 as luminously layer, triphenyl diamine(TPD) as hole transport layer and ZnO(l nm )/ITO(l50 nm) as anode. The result of this experiment was not good compared with the case of using ITO, Nevertheless, at this structure we obtained the lowest turn-on voltage as the value of 19 V and the good brightness (6200 $cd/m^{2}$) of the emission light from the devices. Then the quantum efficiency was to be 1.0%.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1047-1052
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• 2003

Controlling carrier transport in light emitting polymers is extremely important for their efficient use in organic opto-electronic devices [1]. Here we show that the interactions between single wall carbon nanotubes (SWNTs) and conjugated polymers can be used to modify the overall mobility of charge carriers within nanotube-polymer nanocomposites. By using a unique, double emitting-organic light emitting diodes (DE-OLEDs) structure. we have characterized the hole transport within electroluminescent nanocomposites (nanotubes in poly (m-phenylene vinylene-co-2,5-dioctoxy-p-phenylene) or PmPV). We have shown using this idea that single devices with color tunability can be fabricated. It is seen that SWNTs in PmPV are responsible for hole trapping, leading to shifts in the emission wavelengths. Our results could lead to improved organic optical amplifiers, semiconducting devices, and displays.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.96-99
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• 2000

We fabricated electroluminescent(EL) devices which have a blended single emitting layer containing poly(N-vinylcarbazole)[PVK] and poly(3-dodecylthiophene)[P3DoDT]. The molar ratio between P3DoDT and PVK changed with 1:0, 2:1 and 1:1. To improve the external quantum efficiency of EL devices, we applied insulating layer, LiF layer, between polymer emitting layer and Al electrode. All of the devices emit orange-red light and its can be explained that the energy transfer occurs from PVK to P3DoDT. In the voltage-current and voltage-light power characteristics of devices applied LiF layer, current and light power drastically increased with increasing applied voltage. In the consequence of the result, the external quantum efficiency of the devices that have a molar ratio 1:1 with LiF layer was 35 times larger than that of the device without LiF layer at 6V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.2
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• pp.110-118
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• 2002

Organic thin film transitors(OTFT) are of interest for use in broad area electronic applications. And recently organic electroluminescent devices(OELD) have been intensively investigated for using in full-color flat-panel display. We have fabricated inverted-staggered structure OTFTs at lower temperature using the fused-ring polycyclic aromatic hydrocarbon pentacene as the active eletronic material and photoacryl as the organic gate insulator. The field effect mobility is 0.039∼0.17 ㎠/Vs, on-off current ratio is 10$\^$6/, and threshold voltage is -7V. And here we report the study of driving emitting, Ir(ppy)$_3$, phosphorescent OELD with all organic thin film transistor and investigated its electrical characteristics. The OELD with a structure of ITO/TPD/8% Ir(ooy)$_3$ doped in BCP/BCP/Alq$_3$/Li:Al/Al and OTFT with a structure of inverted-stagged Al(gate electrode)/photoacry(gate insulator)/pentacene(p-type organic semiconductor)/ Au(source-drain electrode) were fabricated on the ITP patterned glass substrate. The electrical characteristics are turn-on voltage of -10V, and maximum luminance of about 90 cd/㎡. Device characteristics were quite different with that of only OELD.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.120.2-120
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.120.4-120
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• 1998