• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.106-106
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• 2003

최근 집적형 광소자, 레이저 재료, 자료 저장 또는 통신 기술부문에서 제어된 광학적 성질을 갖는 유기-무기 나노 복합체를 만드는 연구가 많은 관심과 주목을 받고 있다. 유기물인 PEG는 대다수의 금속염을 고정시키는 용매 역할을 하는 polymer로써 액체와 같은 특징을 나타내며 무기물인 silica의 network는 순수한 PEG 시스템보다 좋은 기계적 물성을 나타내며, 투명한 물질을 얻을 수 있게 해 준다. 이에 본 연구에서는 SiO2-PEG의 matrix에 우수한 광학적 성질을 지닌 europium을 doping하여 유기-무기 나노 복합막을 합성하여 europium의 농도와 PEG 분자량에 따른 구조적 및 광학적 성질을 알아보고자 한다.

• Membrane and Water Treatment
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• 제14권4호
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• pp.175-180
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• 2023

Mixed matrix membranes (MMMs) can be a promising alternative for the solution of dye removal from coloured effluents. Polymeric membranes are widely used due to their good film-forming ability, flexibility, separation properties, and cost. However, they have low mechanical, chemical, and thermal resistances. Moreover, the fouling of polymeric membranes is high because of their hydrophobic nature. Hence, there is an increasing interest in organic-inorganic hybrid membranes as a new-generation membrane material. It has been shown that carbon nanotubes have the potential to increase the material properties of polymers with their low density, high strength, hardness, and exceptional aspect ratio. In this work, carbon nanotubes blended MMMs were prepared and methyl orange removal efficiency of them was investigated. Compared to the bare membranes, MMMs showed not only increased hydrophilicity, water content, and pure water flux but also increased methyl orange rejection and flux recovery

• 공업화학
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• 제16권1호
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• pp.112-116
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• 2005

본 연구에서는 생체재료 표면개질의 방법으로 유-무기 박막 형성에 관한 방법을 연구하였다. Collagen의 분해 시 얻어진 gelatin을 polystyrene 배양접시에 2 h 동안 흡착시켜 gelatin 흡착층을 형성하였다. Gelatin 흡착중에 calcium과 phosphorus 과포화 이온용액을 주입하여 calcium phosphate (CaP) 박막을 제조하였다. 박막 형성 초기에 박막의 핵들이 나타나는 것을 관찰하였다. 처리시간에 따라 CaP 박막에 성장하여 배양접시의 바닥표면 전체에 형성된 것을 볼 수 있었다. 형성된 gelatin/CaP 복합 박막의 특징은 3차원 공간에서 다공성이 높은 표면 구조를 형성하였다. Attenuated total reflectance Fourier transform infra-red spectroscopy (ATR-FTIR)을 이용하여 CaP 박막의 화학적 성질을 분석한 결과, 박막 형성 초기에는 무결정 형태의 박막이 형성되고, 시간이 경과됨에 따라 결정성이 약간 증가하지만, 결정성이 낮은 CaP에서 나타나는 흡수피크의 존재 등을 통하여 본 연구에서 제조한 CaP 박막은 poorly crystalline CaP 박막임을 확인하였다.

• 한국세라믹학회지
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• 제52권5호
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• pp.366-373
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• 2015

Sol-gel binder was prepared by hydrolysis and condensation reaction using boehmite sol and methyltrimethoxysilane as a function of aging-time. The coating slurry was composed of a plate-shape alumina in the sol-gel binder for the EPD process, in which particles dispersed in the slurry were deposited on the electrode under an electric field due to the surface charge. We studied the effects of three parameters: the content of boehmite, the aging time, and the applied voltage, on the physical, thermal, and electrical properties of the hybrid composite films by EPD. The amount of boehmite was 10 ~ 20 wt% and the aging time was 0.5 ~ 72, with a fixed amount of plate-shape alumina of 10 wt%. The condition of applied voltage was 5 ~ 30 V with a distance of 2 cm between the electrode during the EPD process. We confirmed that a structure of hybrid composite films of well-ordered plate alumina was deposited on the substrate when the film was prepared using a sol-gel binder composed of 15 wt% boehmite with 1 hr aging time and EPD at 10 V. The process shows a weight loss of 7% at $500^{\circ}C$ in TGA and a breakdown voltage of 8 kV at $87{\mu}m$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.620-621
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• 2008

Transparent electronics has been one of the key terminologies forecasting the ubiquitous technology era. Several researchers have thus extensively developed transparent oxide-based thin-film transistors (TFTs) on glass and plastic substrates although in general high voltage operating devices have been mainly studied considering transparent display drivers. However, low voltage operating oxide TFTs with transparent electrodes are very necessary if we are aiming at logic circuit applications, for which transparent complementary or one-type channel inverters are required. The most effective and low power consuming inverter should be a form of complementary p-channel and n-channel transistors but real application of those complementary TFT inverters also requires electrical- and even photo-stabilities. Since p-type oxide TFTs have not been developed yet, we previously adopted organic pentacene TFTs for the p-channel while ZnO TFTs were chosen for n-channel on sputter-deposited $AlO_x$ film. As a result, decent inverting behavior was achieved but some electrical gate instability was unavoidable at the ZnO/$AlO_x$ channel interface. Here, considering such gate instability issues we have designed a unique transparent complementary TFT (CTFTs) inverter structure with top n-ZnO channel and bottom p-pentacene channel based on 12 nm-thin nano-oxide/self assembled monolayer laminated dielectric, which has a large dielectric strength comparable to that of thin film amorphous $Al_2O_3$. Our transparent CTFT inverter well operate under 3 V, demonstrating a maximum voltage gain of ~20, good electrical and even photoelectric stabilities. The device transmittance was over 60 % and this type of transparent inverter has never been reported, to the best of our limited knowledge.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.427-427
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• 2016

Organic-inorganic hybrid perovskite have attracted significant attention as a new revolutionary light absorber for photovoltaic device due to its remarkable characteristics such as long charge diffusion lengths (100-1000nm), low recombination rate, and high extinction coefficient. Recently, power conversion efficiency of perovskite solar cell is above 20% that is approached to crystalline silicon solar cells. Planar heterojunction perovskite solar cells have simple device structure and can be fabricated low temperature process due to absence of mesoporous scaffold that should be annealed over 500 oC. However, in the planar structure, controlling perovskite film qualities such as crystallinity and coverage is important for high performances. Those controlling methods in one-step deposition have been reported such as adding additive, solvent-engineering, using anti-solvent, for pin-hole free perovskite layer to reduce shunting paths connecting between electron transport layer and hole transport layer. Here, we studied the effect of alkali metal halide to control the fabrication process of perovskite film. During the morphology determination step, alkali metal halides can affect film morphologies by intercalating with PbI2 layer and reducing $CH3NH3PbI3{\cdot}DMF$ intermediate phase resulting in needle shape morphology. As types of alkali metal ions, the diverse grain sizes of film were observed due to different crystallization rate depending on the size of alkali metal ions. The pin-hole free perovskite film was obtained with this method, and the resulting perovskite solar cells showed higher performance as > 10% of power conversion efficiency in large size perovskite solar cell as $5{\times}5cm$. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectrometry (ICP-OES) are analyzed to prove the mechanism of perovskite film formation with alkali metal halides.

• Korean Chemical Engineering Research
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• 제40권6호
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• pp.735-740
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• 2002

고분자 필름의 무적성을 향상시키기 위하여 우수한 친수성 및 높은 가시광선 투과율을 보이는 유기-무기 혼성 코팅용액을 졸-겔법으로 합성하였다. 코팅용액은 입자 직경이 15 nm 크기의 무기물인 콜로이드 실리카 용액(Ludox)에 유기 조성을 함유한 화합물인 GPS을 첨가하여 제조되었다. 실란 커플링제인 GPS는 콜로이드 실리카와 주변의 매트릭스(matrix)인 고분자 필름에 각각 강한 결합을 형성하여 두 개의 서로 다른 물질을 강하게 연결하는 결합제 역할을 한다. 강산성 조건 하에서 제조된 혼성 코팅용액으로 고분자 필름 위에 코팅한 경우는 코팅필름의 표면이 거의 균열이 없는 매끈한 미세구조를 보이는 반면, 약산과 염기성 조건 하에서 제조된 혼성 코팅용액으로 코팅한 경우에는 균열이 심한 미세구조를 보였다. 또한 pH 2의 산성 조건에서 제조한 필름은 우수한 친수성 및 높은 가시광선 투과율을 보인 반면, 염기성 조건으로 제조한 코팅필름은 친수성이 좋지 않았으며, 낮은 가시광선 투과율을 보였다.

• Korean Chemical Engineering Research
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• 제45권4호
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• pp.335-339
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• 2007

투명 polycarbonate(PC) 시트의 낮은 표면강도 문제를 극복하기 위해, 고굴절률을 보이는 유-무기 혼성 하드코팅 용액을 Sol-Gel 법을 이용하여 제조하였다. 코팅용액은 무기물 티타니아의 전구체인 TTIP(titanium tetraisopropoxide)에 유기물을 함유한 화합물인 GPTMS[(3-glycidoxypropyl) trimethoxysilane]를 첨가하여 제조하였다. 그 후 기재인 PC 시트에 스핀 코팅시키고, 열 경화 시켜 고굴절률을 보이는 하드코팅 필름을 제조 하였다. 코팅 용액 중의 GPTMS 함유량을 변화시킴에 의해 1.53-1.61의 굴절률을 갖는 코팅 막의 제조가 가능하였다. GPTMS의 첨가량이 증가할수록 코팅막의 굴절률은 감소하였으나, 연필경도는 증가하였다.

• 한국세라믹학회지
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• 제48권6호
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• pp.499-503
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• 2011

Recently, variety of organic and inorganic hybrid materials have recently investigated as alternative routes to SiOC, $SiO_2$ thin film formation at low temperatures for applications in electronic ceramics. Specially, silicon based polymers, such as polycarbosilane, polysilane and polysilazane derivatives have been studied for use in electronic ceramics and have been applied as dielectric or insulating materials. In this study, Polycarbosilane(PCS), which Si-$CH_2$-Si bonds build up the backbone of the polymer, has been investigated as low-k materials using a solution process. After heat treatment at 350$^{\circ}C$ under $N_2$ atmosphere, chemical composition and dielectric constant of the thin film were $SiO_{0.27}C_{1.94}$ and 1.2, respectively. Mechanical property measured using nanoindentor shows 1.37 GPa.

• ETRI Journal
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• 제36권5호
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• pp.847-855
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• 2014

We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of $TiO_2$ solutions for a planarization of the embossed nano-structure on a glass substrate. The first $TiO_2$ solution was $TiO_2$ sol, which consists of $TiO_2$ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of $TiO_2$. The surface roughness ($R_a$) and refractive index of the $TiO_2$ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the $TiO_2$ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.