• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.21-22
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• 2006

Significant progress has been realized in the design and synthesis of light emitting polymers with emission over the whole range of the visible spectrum. However up to seventy-five percent of charge recombination events can lead to triplet states that decay non-radiatively. Following the pioneering work in the field of small molecule organic light emitting devices it has been found that solution processible iridium polymer complexes can be used to harness the wasted triplet energy. In this paper new results concerning electrophosphorescence of solution processible tethered iridium polymer derivatives will be presented. Furthermore our approaches to the design of new high triplet energy conjugated polymer hosts will be reported.

• 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 Vacuum Society Conference
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• 2014.02a
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• pp.484.1-484.1
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• 2014

Bulk hetero junction (BHJ) polymer solar cells (PSCs) are one of the most promising fields as alternative energy source. Especially, the development of new p-type conjugated polymer is one of the main issues to get core technology. In this study, a series of varied ratio of 3,6-carbazole in poly[9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl-alt-(5,6-bis-(octyloxy)-4,7-di(thiophen-2-yl)benzo-[1,2,5]-thia-diazole)-5,5-diyl] were designed and synthesized. These polymers have good solubility and film formability than PCDTBT which is well known promising material. Investigation of the photovoltaic properties of these new polymers indicated that polymer with 2% of 3,6-carbazole provided higher PCE (3.8% to 4.9%) with enhanced JSC, FF, VOC. We found origin of this improvement using several methods, one of which is reduced bimolecular recombination in polymer.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.123-124
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• 2000

Three types of conjugated polymer, poly(DFPZ-AV), poly(MEHPV-PV) and poly(BFMP12-BPV), were obtained by Honer-Emmons condensation using potassium tert-butoxide from the synthesized monomers in anhydrous tetrahydrofurane. The Honer-Emmons reaction was found to be a useful synthetic method for the preparing a wide range of EL polymers. The EL devices using poly(DFPZ-AV), poly(MEHPV-PV) and poly(BFMP12-BPV) as light emitting layer gave red, green and blue emission, respectively, which were in close chromaticity with the CIE 1931 NTSC standard.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.187-190
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• 1996

Conducting polymers have band structures similar to those of inorganic semiconductors such as silicon. Several electronic devices have been constructed with conjugated polymers, mainly Schottky diodes and Metal-Insulator-Semiconductor Field-Effect Transistors (MISFET's). Organic semiconductor has been reported as active materials in MISFET's.$^{1.4}$ In our laboratory, $\alpha$-Sexithiencyl ($\alpha$-6T) has been synthesized and purified by sublimation method. In this study, thin films of $\alpha$-Sexithienyl were prepared on various substrates in ultra-high vacuum chamber by vacuum evaporation method, so called OMBD(Organic Molocular Beam Deposition).$^{7.9}$ The $\alpha$-Sexithienyl thin films were deposited with various deposition conditions. The crystalline structure, and molecular orientation of these films have being studied by using UV/Vis. spectroscopy and X-Ray Diffractometry.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1418-1421
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• 2009

A series of new light-emitting random copolymers with fully conjugated structure was prepared, for the first time through the well-known Gilch polymerization between 1,4-bis(chloromethyl)-2-ethylhexyloxy-5-methoxybenzene and 2,5-bis(bromomethyl)thiophene monomers in different ratios. The synthesized polymers (on thin film) showed the maximum wavelength of UV-visible absorbance and photoluminescence (PL) near 500 nm and near 600 nm, respectively. A single-layer light-emitting diode device, which has a simple ITO (indium-tin oxide)/polymer/Al configuration, was fabricated by spin-coating of polymers and then vacuum evaporation of Al metal. The threshold bias of PMEHPVTVs was in the range of 3.5-10 V. As in the PL spectra, the maximum wavelength of light emission near 600 nm was also shown in electroluminescence (EL) spectra of PMEHPVTVs when the operating voltage was about 7 - 14 V.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.451-455
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• 1999

The polymerization of 2-ethynylpyridine by alkyl bromide carrying carbazole moiety, 6-(N-carbazolyl)hexyl bromide, relatively proceed well to give the corresponding poly[6'-(N-carbazolyl)hexyl-2-ethynylpyridinium bromide) in high yields under DMF reflux conditions without any initiator or catalyst. This polymerization was influenced upon the initial monomer concentration. The polymer yields and inherent viscosities of the resulting polymers were in the range of 34-85% and 0.11-0.21 dL/g, respectively. Instrumental analyses using NMR, IR, and UV-visible spectroscopies and elemental analysis indicated that the resulting polymer has a conjugated polymer backbone system carrying pyridine and n-hexyl carbazole moiety. The polymers were mostly brown powders and completely soluble in DMF, DMSO, nitrobenzene, and formic acid. The photoluminescence spectrum of the dilute polymer solution with the excitation at 383 nm exhibited two sharp peaks at 495 and 540 nm.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.53-56
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• 2002

Today, interest in electroluminescent(EL) diodes has been increasing since vacuum-sublimed thin-film dioes exhibited high performance. And since the discovery of electroluminescence from aluminaqinone, which has uniform $\pi$-conjugated segment by Eastmann kodack,$^1$ lots of attentions have been concentrated on organic EL devices. However, they have disadvantage such as low mechanical intensity, thermic crystallization. (omitted)

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.459-460
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• 2007

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• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.76-77
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• 2006

Conducting polymers have been attracting considerable attention from both scientific and industrial perspectives by virtue of the beneficial electrical and optical properties originating from their unique ${\pi}-conjugated$ system. Many efforts have been devoted toward fabricating conducting polymer nanomaterials. Of the various synthetic methodologies, soft template method has emerged as a very promising tool in fabricating conducting polymer nanomaterials. For last a few years, our research group has intensively studied the fabrication and application of conducting polymer nanomaterials. In this talk, the recent achievement in the synthetic methodology based on the use of soft templates will be discussed.