• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.98-101
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• 2002

The effect of morphology on energy transfer and device performance in phosphorescent dye doped polymer light emitting diodes is reported. We selected two host polymers (PVK and PFHP) which have nearly the same potential for the energy transfer to Ir(ppy)$_3$. The PFHP:Ir(ppy)$_3$ film showed b-micron size aggregation, whereas the PVK:Ir(ppy)$_3$ film showed homogeneous and smooth images. As a result, energy transfer is efficient with high emission efficiency in PVK:Ir(ppy)$_3$ whereas little energy transfer and low quantum efficiency are obtained in PFHP:Ir(ppy)$_3$.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.166-169
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• 2009

Poly(benzimidazole-co-aniline) (PBIANI), a self-crosslinked, net-structured, proton conducting polymer has been synthesized for the membrane of high temperature proton exchange membrane fuel cells (HT-PEMFC) with improved proton conductivity and mechanical strength. The stress at break (26$\pm$3MPa)and proton conductivity (167 mS cm-1)of the phosphoric acid doped PBIANI (DPBIANI)membrane is much higher than those of other doped polybenzimidazole(PBI) type membranes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.311-312
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• 2007

In this study, composite $BaSrTiO_3$ has been studied for high frequency device applications. Composite $Ba_{0.5}Sr_{0.5}TiO_3$ has high dielectric permittivity and low loss tangent at the relative frequency range from MHz to GHz. 10,30 and 50 wt% of epoxy doped $Ba_{0.5}Sr_{0.5}TiO_3$ powders were prepared with bisphenol A and F polymer employing ball milling process. Epoxy/($BaSrTiO_3$) composites thick films were screen printed on the Cu plated PCB substrates through screen printing methods. The specimens were designed for the embedded capacitor applications. Temperature dependent dielectric permittivity of Epoxy doped $BaSrTiO_3$ ceramics was measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.535-538
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• 2004

Zinc Oxide (ZnO) films have attracted considerable attention for transparent conducting films, because of their high conductivity, good optical transmittance from UV to near IR as well as a low-cost fabrication. To increase the conductivity of ZnO, doping of group III elements (Al, Ga, In and B) has been carried out. Transparent conducting films have been applied for optoelectric devices, the development of the transparent conducting thin films on flexible light-weight substrates are required. In this research, the transparent conducting ZnO thin films doped with Aluminum (Al) on polymer substrates were deposited by the RF magnetron suputtering method, and the structural, optical and electrical properties were investigated.

• Membrane Journal
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• v.32 no.6
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• pp.442-455
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• 2022

High-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has been studied as an alternative to low-temperature PEMFC due to its fast activation of electrodes and high resistance to electrode poisoning by carbon monoxide. It is highly required to develop stable PEMs operating at high temperatures even doped by ion-conducting materials for the development of high-performance and durable HT-PEMFC systems. A number of studies have been conducted to develop polybenzimidazole (PBI)-based PEMs for applications in HT-PEMFC due to their high interaction with doped ion-conducting materials and outstanding thermomechanical stability under high-temperature operation. This review focused on the development of PBI-based PEMs showing high performance and durability. Firstly, the characteristic behavior of PBI-based PEMs doped with various ion-conducting materials including phosphoric acid was systematically investigated. And then, a comparison of the physicochemical properties of the PEMs according to the different membrane manufacturing processes was conducted. Secondly, the incorporation of porous polytetrafluoroethylene substrate and/or inorganic composites to PBI matrix to improve the membrane performances was studied. Finally, the construction of cross-linked structures into PBI-based PEM systems by polymer blending method was introduced to improve the PEM properties.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.664-671
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• 1998

Poly pyrrole polymer(ppy) has an excellent electrical conductivity and can be easily polymerized on anode to give various morophology according to doped anion on electroactive sites. To improve the properties of brittleness, ageing and hydrophobisity, poly furan polymer(pfu) having a high initiation potential was anodically implanted in this porous ppy film matrix to get the Pt/ppy/pfu(x)type of polymer composite electrode. Cyclic voltammetry and electrochemical impedance methods were used to these electrode, where $PF_6^-,\; BF_4^-$, and $ClO_4^-$ ions were employed as dopants. The composition of the pfu(x) at the electrode was changed from 0 to 1.10, but the range was useful only at 0.1 to 0.2 as the redox electrode. The polymer composite electrode doped with $PF_6^-$ was better in charge transfer resistance by a factor of 40 times and in double layer capacitance by a factor of 20 times than others. The charge transfer in the polymer film of the electrode was influenced on frequency change and equivalent circuit of this electrode had Warburg impedance including mass transfer.

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.89-89
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• 1996

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.599-601
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• 2004

A new blue electroluminescent conjugated polymer, poly(BP-alt-BCV), was prepared by Hornor-Emmons polycondensation and used as a host polymer for the phosphorescent dopant, $(bsn)_2Ir(acac)$. Poly(N-vinylcarbazole) (PVK), known as a blue EL material, was also used for comparison with poly(BP-alt-BCV). Electrophosphorescence of PLEDs with these dopant/host systems was investigated in terms of luminescence, efficiency, emission color, and energy transfer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.101-105
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• 1998

This paper describes anisotropic etching technology of highly doped polysilicon. The main etching gases are $Cl_2$ and $SiCl_4$ for reactive ion etching of polysilicon. The mixed $CHCl_3$ to main etching gas makes polymer on etching side wall, so it prevents side etching of polysilicon. The etch rate of polysilicon is increased with increasing RF power. But the etching rate is decreased as the flow rate of $CHCl_3$ is increased with fixed RF power. The etch selectivity of polysilicon and $SiO_2$ is about 12:1. And that of polysilicon and $Si_3N_4$ is about 19:1. In the main etching gas condition, the slope of polysilicon is same as that of photoresist. But in the mixed $CHCl_3$ condition, the slope of polysilicon is larger than that of photoresist. This represents that the polymer made on side wall by added $CHCl_3$ prevents side etching, so anisotropic etching can be possible by polymer.

• Polymer(Korea)
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• v.37 no.1
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• pp.66-73
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• 2013

Three reactive dichroic dyes with 3,5-dichloro-2,4,6-triazine moiety were synthesized by reaction between dichroic dyes (such as congo red, direct black 22 or direct black 4) and cyanuric chloride. Poly(vinyl alcohol) (PVA) films were dyed with the obtained three reactive dichroic dyes. After 400% drawing of the PVA films, their optical properties were compared with an iodine-doped PVA film prepared in the same condition. Durability test was performed at $50^{\circ}C$ in 85% of relative humidity for 120 hrs. We found that compared with the iodine-doped PVA polarizing film, the relative durability of the PVA polarizing film dyed with the reactive dichroic dyes was greatly improved.