• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.317.2-317.2
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• 2013

Ultrathin oxide encapsulated metal-oxide hybrid nanocatalysts have been fabricated by a soft chemical and facile route. First, SiO2 nanoparticles of 25~30 nm size have been synthesized by modified Stobber's method followed by amine functionalization. Metal nanoparticles (Ru, Rh, Pt) capped with polymer/citrate have been deposited on functionalized SiO2 and finally an ultrathin layer of TiO2 coated on surface which prevents sintering and provides high thermal stability while maximizing the metal-oxide interface for higher catalytic activity. TEM studies confirmed that 2.5 nm sized metal nanoparticles are well dispersed and distributed throughout the surface of 25 nm SiO2 nanoparticles with a 3-4 nm TiO2 ultrathin layer. The metal nanoparticles are still well exposed to outer surface, being enabled for surface characterization and catalytic activity. Even after calcination at $600^{\circ}C$, the structure and morphology of hybrid nanocatalysts remain intact confirm the high thermal stability. XPS spectra of hybrid nanocatalyst suggest the metallic states as well as their corresponding oxide states. The catalytic activity has been evaluated for high temperature CO oxidation reaction as well as photocatalytic H2 generation under solar simulation. The design of hybrid structure, high thermal stability, and better exposure of metal active sites are the key parameters for the high catalytic activity. The maximization of metal-TiO2 interface interaction has the great role in photocatalytic H2 production.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3183-3184
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• 2013

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.25-37
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• 2020

본 연구에서는 그래핀 소재의 전기전도성 및 자기적 특성을 향상시키기 위해 산화그래핀 표면상의 산소를 포함한 기능기와 열처리 환원공정을 이용하여 환원그래핀과 금속소재를 하리브리드화 하였다. 산화 그래핀 표면의 -OH, -COOH 등의 산소 포함 기능기들을 열처리 환원시킴과 동시에 금속이온을 기능기와의 이온교환법에 의해 치환 합성하는 연구를 진행하였다. 하이브리드 소재 합성에 사용된 금속은 Fe, Ag, Ni, Zn, Fe/Ag이며 SEM, TEM 및 EDS를 통해 환원 그래핀 표면 위에 균일한 크기의 금속 입자가 비교적 구형 잘 분산되었음을 확인하였다. 그래핀 표면상의 금속입자들은 모두 산화물 형태의 구조를 가지고 있었다. 하이브리드 소재의 전기적 특성을 확인하기 위해 rGO-metal hybrid 시료를 PET film에 dip-coating 방법으로 후막 필름을 형성시킨 후 면저항을 측정하였고, SEM을 통해 시편의 두께를 측정하여 비저항을 계산한 결과, 비저항의 범위는 2.14×10-5 ~ 3.5×10-3 ohm/cm범위에 있음을 확인하였다.

• 한국전자통신학회논문지
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• 제4권4호
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• pp.301-305
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• 2009

Pt 나노입자의 합성과 이를 이용한 hybrid Pt-$SiO_2$ 나노입자의 합성을 성공적으로 수행하였으며, self-assembled Pt nanoparticles monolayer를 charge trapping layer로 활용하는 metal-oxide-semiconductor(MOS) type memory의 한 예로 non-volatile memory(NVM)의 응용을 보임으로써 나노입자의 활용 가능성을 보이고, 또한, hybrid Pt-$SiO_2$ 나노입자 박막 층의 제어를 통한 MOS type memory device에의 보다 더 넓은 활용 가능성을 보이고자 하였다.

• 정보저장시스템학회논문집
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• 제9권1호
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• pp.22-27
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• 2013

In this paper we are presenting a architecture of Co ion decorated graphene oxide as an electrode for supercapacitor application. Graphene oxide, which is exfoliated by oxidant from graphite, is the material for solving the problem of mass production and coating on the surface of working electrode. The $Co^{2+}$ ions are coated by using layer by layer(LBL) method on graphene oxide foam. The metal ion decorated graphene oxide shows enhanced capacitance performance when tested as supercapacitor electrode, showing the specific capacitance of $827Fg^{-1}$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.311-311
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• 2013

The resistance switching memory devices have several advantages to take breakthrough for the limitation of operation speed, retention, and device scale. Especially, the metal-oxide materials such as ZnO are able to fabricate on the flexible and visible transparent plastic substrate. Also, the quantum dots (QDs) embedded in dielectric layer could be improve the ratio between the low and the high resistance becauseof their Coulomb blockade, carrier trap and induced filament path formation. In this study, we irradiated 0.2-MeV-electron beam on the ZnO/QDs/ZnO structure to control the defect and oxygen vacancy of ZnO layer. The metal-oxide QDs embedded in ZnO layer on Pt/glass substrate were fabricated for a memory device and evaluated electrical properties after 0.2-MeV-electron beam irradiations. To formation bottom electrode, the Pt layer (200 nm) was deposited on the glass substrate by direct current sputter. The ZnO layer (100 nm) was deposited by ultra-high vacuum radio frequency sputter at base pressure $1{\times}10^{-10}$ Torr. And then, the metal-oxide QDs on the ZnO layer were created by thermal annealing. Finally, the ZnO layer (100 nm) also was deposited by ultra-high vacuum sputter. Before the formation top electrode, 0.2 MeV liner accelerated electron beams with flux of $1{\times}10^{13}$ and $10^{14}$ electrons/$cm^2$ were irradiated. We will discuss the electrical properties and the physical relationships among the irradiation condition, the dislocation density and mechanism of resistive switching in the hybrid memory device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.801-804
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• 2002

Electrochemical capacitors are becoming attractive energy storage systems particularly for applications involving high power requirements such as hybrid systems consisting of batteries and electrochemical capacitors for electric vehicle propulsion. Both of amorphous cobalt oxide and manganese dioxide were prepared by sol-gel process reported in our previous work. Nanostructured supramolecular oligomer of 1,5-diaminoanthraquinone(DAAQ) coated metal oxides were successfully prepared by electrochemical oxidation from an acidic non-aqueous medium. We established process parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured metal oxide electrodes using controlled solution chemistry. $CoO_2$ and $MnO_2$-based composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency.

• 한국세라믹학회지
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• 제55권5호
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• pp.407-418
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• 2018

Increasing demand for portable and wireless electronic devices with high power and energy densities has inspired global research to investigate, in lieu of scarce rare-earth and expensive ruthenium oxide-like materials, abundant, cheap, easily producible, and chemically stable electrode materials. Several potential electrode materials, including carbon-based materials, metal oxides, metal chalcogenides, layered metal double hydroxides, metal nitrides, metal phosphides, and metal chlorides with above requirements, have been effectively and efficiently applied in electrochemical supercapacitor energy storage devices. The synthesis of self-grown, or in-situ, nanostructured electrode materials using chemical processes is well-known, wherein the base material itself produces the required phase of the product with a unique morphology, high surface area, and moderate electrical conductivity. This comprehensive review provides in-depth information on the use of self-grown electrode materials of different morphologies in electrochemical supercapacitor applications. The present limitations and future prospects, from an industrial application perspectives, of self-grown electrode materials in enhancing energy storage capacity are briefly elaborated.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.779-780
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• 2009

New inverted architecture of a hybrid inorganic-organic light-emitting diode, utilizing ZrO2 electron-injecting layer, is presented. The thickness of the ZrO2, as well as the annealing of the light-emitting polymer, is found critical to obtain good performance. A range of light-emitting polymers is shown to operate efficiently in the proposed architecture.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.11.2-11.2
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• 2011

A key technological issue related to the implementation of dye-sensitized solar cells (DSSCs) is the replacement of Pt at the counter electrodes with an inexpensive and electro-chemically stable alternative. Carbon based nanomaterials could be promising candidates, but in practice they exhibit inadequate device performance. Here, we report very thin graphene oxide (GO)/metal hybrid films as transparent counter electrodes for high-efficiency DSSCs. Transparent GO/Pt and GO/Au hybrid films showed cell efficiencies of 9.2 and 9.0%, respectively (improvements of 9.5 and 7.1% over conventional Pt counter electrodes). More interestingly, highly stable DSSCs with GO hybrid films from relatively inexpensive metals such as Cu and Ni have been demonstrated with efficiency values comparable to Pt counter electrodes. The results reported in this study should enable low-cost fabrication of DSSCs because it allows the use of relatively inexpensive metals such as Au, Cu, Ni, and Ag that could not be previously employed in DSSCs with iodide/tri-iodide electrolyte due to corrosion.