• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.975-978
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• 2001

A novel poly[9,10-diphenylanthracene-4',4"-ylenevinylene-3,6-(N-2-ethyl hexyl)carbazole] containing alternate diphenylanthracene and carbazole unit was synthesized by the Wittig reaction. The obtained polymer was soluble in common organic solvents and thermally stable up to 380 $^{\circ}C.$ The polymer gives rise to bright blue fluorescence both in solution and in thin solid films. The light emitted from the device (ITO/polymer/Al) was greenish-blue in color and clearly visible in daylight.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1319-1322
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• 2008

$CsN_3$ was developed as a novel n doping material with air stability and low deposition temperature. Evaporation temperature of $CsN_3$ was similar to that of common hole injection material and it worked well as a n dopant in electron transport layer. Driving voltage was lowered and high power efficiency was obtained in green phosphorescent devices by using $CsN_3$ as a dopant in electron transport layer. It could also be used as a charge generation layer in combination with $MoO_3$. In addition, n doping mechanism study revealed that $CsN_3$ is decomposed into Cs and $N_2$ during evaporation. This is the first work reporting air stable and low temperature evaporable n dopant in organic light-emitting diodes.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1805-1808
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• 2006

In this paper, we describe a versatile use of fullerene(C60) as a charge transporting material for organic light-emitting diodes. The use of fullerene as a buffer layer for an anode, a doping material for hole transport layer, and an electron transport layer was investigated. Fullerene improved the hole injection from an anode to a hole transport layer by lowering the interfacial energy barrier and enhanced the lifetime of the device as a doping material for a hole transport layer. In addition, it was also effective as an electron transporting material to get low driving voltage in the device.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.254-258
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• 2009

We herein report on polymer phosphorescent light-emitting devices doped with iridium complex. The emitting layer of poly(N-vinylcabazole) and tris(2-phenylpyridine)iridium was fabricated by low speed dip-coating of 10, $20{\mu}m$/s. The devices showed stable current increasing leakage current at turn-on voltage. Compared to conventional spin-coating based organic light-emitting devices, the driving voltage by dip-coating observed lower values of 5.8 and 6.7 V at the luminance of 100 Cd/$cm^2$.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.810-813
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• 2009

Fluorene derivatives are well-known in the polymer OLEDs due to their good charge carrying property. In this work, we synthesized a series of conjugated copolymers based fluorene derivative and phenylamine units by using Buchwald-Hartwig reaction in order to investigate their photoreactivities and use as the HIL/HTL layers of OLEDs using solution processes.

• Macromolecular Research
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• v.13 no.2
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• pp.114-119
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• 2005

We synthesized two new series of alternating copolymers, poly[bis(2-(4-phenylenevinylene)-2-cyanoethenyl)-9,9-dihexyl-9H-fluoren-2,7-yl-alt-1,4-phenylene](Polymer-I)and poly[bis(2-(4-phenylenevinylene)-2­cyanoethenyl)-9,9-dihexyl-9H-fluoren-2,7-yl-alt-2,7-(9,9-dihexylfluorene)](Polymer-II), via the Suzuki coupling reaction, for use in light-emitting diodes (LEDs). Defect-free uniformly thin films of these polymers were found to be easily formed on indium-tin oxide (ITO) coated glass substrates. Multi-layer LEDs with ITO/PEDOT/Polymer/ LiF/Al configurations with or without an $Alq_3$ electron transport layer were fabricated with these polymers. The maximum EL emissions of Polymer-I and Polymer-II with an $Alq_3/LiF/Al$ cathode were observed at 516 and 533 nm, respectively. The maximum brightness and external luminance efficiency of the devices fabricated with the EL polymers were found to be $411 cd/m^2$ and 0.16 cd/A, respectively.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.464-468
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• 2012

Three solvent systems, chlorobenzene (ink 1), chlorobenzene/o-dichlorobenzene (ink 2) and chlorobenzene/tetrahydronaphthalene (ink 3), were compared as printable inks for the fabrication of polymer light-emitting diodes (PLEDs) using poly[2-methoxy-5-(2-ethylhexyl-oxyl)-1,4-phenylenevinylene (MEH-PPV) as an emissive material and an inkjet printer (Fujifilm Dimatix DMP-2831). Ink 1 clogged the printer's nozzle and gave non-uniform film. Inks 2 and 3 were used to fabricate PLEDs with ITO/PEDOT:PSS/MEH-PPV/LiF/Al configurations. The best performance (turn-on voltage, 3.5 V; luminance efficiency, 0.17 cd/A; luminance, 1,800 cd/m) was obtained when ink 3 was used to form the emissive layer (thickness, 49 nm), attributable to the better morphology and suitable thickness of the MEH-PPV layer.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.7-10
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• 2003

Blue-light-emitting peiymer/dielectric nanolayer nanocomposites were prepared by the solution intercalation method and employed in electroluminescent device. Their photoluminescence and electroluminescence characteristics suggested that the nanolayers isolate the polymer chains and hinder the formation of excimers and aggregates. By reducing the excimer formation and its deleterious effects on emission efficiency, both the color purity and the luminescence stability were improved. Furthermore, the dielectric nanolayers have an aspect ratio of about 500 and therefore act as efficient barriers to oxygen and moisture diffusion, which produced a dramatic increase in the device stability.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.235-235
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• 2006

Triphenylamine derivatives play important roles as hole transporting materials in organic light emitting devices. However, low molecular weight triphenylamine derivatives show low glass transition temperature and aggregation behavior, and the vapor deposition step of low molecular weight materials is incompatible with large area display fabrication. Conventional polymer PEDOT-PSS HTL has serious drawbacks such as the ITO anode corrosion, poor surface energy match with aromatic EMLs. To solve these problems, we introduced crosslinkable units to triphenylamine-based polymers to make insoluble HTL by thermal curing following spin-coating. Electrochemical and optical properties of the new hole transporting materials were investigated. In addition, the device characteristics obtained with new hole transporting polymers were investigated in details.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.51-56
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• 2006

Polymer light emitting diodes (PLEDs) with ITO/EDOT:PSS/PVK/PFO-poss/LiF/Al structures were prepared by the spin coating method on ITO(indium tin oxide)/glass substrates. PFO-poss[Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with poss] was used as light emitting polymer. PVK[poly(N-vinyl carbazole)] and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] polymers were used as the hole injection and transport materials. The effect of PFO-poss concentration and the heating temperatures on the electrical and optical properties of the devices were investigated. At the same concentration of PFO-poss solution, the current density and luminance of PLED device tend to increase as the annealing temperature increase from $100^{\circ}C$ to $200^{\circ}C$. The maximum luminance was found to be about 958 cd/m2 at 13V for the PLED device with 1.0 wt% PFO-poss at the annealing temperature of $200^{\circ}C$. In addition, the PLED device showed bluish white emission through the strong greenish peak with 523 nm in wavelength. As the concentration of PFO-poss increase from 0.5 wt% to 1.0 wt% and temperature of PLEDs increase from $100^{\circ}C$ to $200^{\circ}C$, the emission color tend to be shifted from blue with (x, y) = (0.17,0.14) to bluish white with (x, y) : (0.29,0.41) in CIE color coordinate.