• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.60.1-60.1
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• 2010

Chemically functionalized plant oils such as acrylated epoxidized soybean oil (AESO) and maleinized acrylated epoxidized soybean oil (MAESO) were used as new bio-based binders for $TiO_2$ electrodes of dye-sensitized solar cells (DSSC). More porous networks and larger porosities were fabricated on the $TiO_2$ films using plant oil binders due to the larger number of functionalities, in comparison with the film using polyethylene glycol (PEG). The charge-transfer resistance in the $TiO_2$ films was considerably shrunk due to the reduced impurity states. The short circuit photocurrent (Isc) and the open circuit photovoltage (Voc) of the cell using plant oil binders increased and the conversion efficiency improved significantly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.240-240
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• 2010

In this paper, in these case of photoelectrode using UV treatment after oxygen solar conversion efficiency is increased. According to oxygen injection UV treatment will removal residual organics and increase the TiO2 surface area but also UV treatment can affect the same chemical action of ozone treatment. More porous networks and larger porosities were obtained in the TiO2 films prepared UV treatment after oxygen injection.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.299-300
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• 2015

$TiO_2$는 내구성이 뛰어난 전기변색재료로 연구가 이루어 지고 있다. 큰 굴절율로 인해 높은 투과율을 보이는 $TiO_2$는 변색시 치밀한 구조를 가지기 때문에 전해질 양이온의 침입이 힘들어 변색효율이 $WO_3$에 비해 좋지 않다. 이를 개선하고자 작업압력을 변화시켜 기판에 입사하는 입자의 에너지를 줄임으로써 확산을 줄이고 Porous한 막을 얻고자 하였다. 작업압력이 높아짐에 따라 표면의 거칠기가 커지는 것을 확인하였고 전기변색시 효율이 커지는 것을 확인하였다.

• Korean Journal of Metals and Materials
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• v.47 no.5
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• pp.267-273
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• 2009

Three types of structural intermetallic compounds, $Ni_3Al$, NiAl and TiAl, having each single phase structure without pores were produced by arc-melting process. Their sliding wear properties were investigated against a hardened tool steel. It was shown that the wear of the intermetallic compounds was hardly occurred against the hardened tool steel. TiAl compound showed the best wear resistance among them. In this case, wear was preferentially occurred on the surface of the hardened tool steel of the mating material which has higher hardness. It could be found that the wear mode on intermetallics without pores by arc-melting process was different from that on its porous layer coated on steel by combustion synthesis.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.361-369
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• 2008

The purpose of this study is to make porous oxide film on the surfaces of pure Ti through anodic spark discharge in electrolytic solution containing calcium and phosphate ions, to improve osseointergration by treating fluoride agent. In addition, it is to evaluate the fluoride modified effect on the surface. Commercial pure Ti plate with $20{\times}10{\times}2mm$ and Ti wire with a diameter of 1.5mm and a total length of 15mm were used. After making titanium oxide films converted by anodic spark discharge, anodizing was performed. Fluoride was spreaded to titanium laboratory plate and maintained for 30 minutes after anodizing breakdown. Fluoride ion discharge amount was measured per 24 hours after dipping titanium plate into saline (10ml) and sustaining 90rpm in a pyrostat. Some plates and wires were dipped in Hanks solutions for a month to examine biocompatibility using SEM and XRD. $TiO_2$ film formed by anodic discharge technique showed great roughness and uniform pores which were $1{\sim}3{\mu}m$ in a diameter. Roughness of the films treated with anodic discharge after blasting were higher than the turned ones(P<0.05). Rapid surface activity was observed in the samples treated with $TiF_3$ agent, which immersed in Hanks solution for 30 days. Taking the results into consideration, the fluoride modified implant with anodic discharge demonstrates that it makes uniformly porous oxide film on the surface of implant and properly increase roughness for osseointegration. The implants will achieve greater bone integration after short healing time by improving surface activity.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.94-100
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• 1994

The junction failure mechanism of W plugs has not been fully understood while the selective W deposition has been widely used for plugging interconnection lines. In this paper, the thermal stability and junction failure mechanism of sub-micron contacts using selective CVD-W plugs were intensively studied with the metal lines of AISiCu, Ti/AISiCu and TiN/AISiCu. The experimental results showed that the contact chain resistance and leakage current in the AISiCu and Ti/AISiCu metallizations were significantly degraded after annealing. From the SEM analysis, it was found that the junction spiking, due to the Al atoms diffusion along the porous interface between selective CVD-W and contactside wall, caused the junction failure. In constast, there was no degradation of the contact resistance and junction leakage current in TiN/AISiCu metal structu-re. It is believed that the TiN barrier layer could prevent AI(Ti) atoms Fromdiffusing. Therefore, TiN barrier between W plug and Al should be used to impro-ve the thermal stability of sub-micron contacts using the selective CVD-W plugs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.117-118
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• 2007

In this paper, we examined an effect by the binder in titanium dioxide film for dye sensitized solar cell. Binder(PEG and PEO) was added the quantity of 10- 40wt% to commercial $TiO_2$ (P25), Respectively. All of $TiO_2$ film was showed porous structure. but difference of film's porosity could not be confirm. Transmittances of $TiO_2$ film was decreased with the increase of binder's quantity, generally. In case of 20wt%, however, Transmittances of $TiO_2$ film was recoded the highest value. and it measured 1.77 of energy-conversion efficiency.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1185-1188
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• 1998

Layered nanocomposite, SiO2/TiO2 sol pillared clay, has been prepared by the ion exchange reaction of Na' ion in montmorillonite with positively charged mixed SiO2/TiO2 sol. The nanosized sol particles were synthesized by mixing SiO2 sol solution with TiO2 one, which is obtained by acidic hydrolysis of TEOS and TiCl4, respectively. From powder XRD, the basal spacing (d001) of the sample calcined at 400 ℃ was found to be ca. 60 Å, due to the multistacking of nanosized SiO2 and TiO2 sol particles, which was confirmed by the pore size analysis from 129Xe NMR and micropore analysis calculated from nitrogen adsorption. The BET specific surface area shows the value of 684 m2g-1 (Langmuir 1115 m2g-1), which is the highest among various pillared clays ever reported previously, and the total porosity is found to be 0.51 mlg-1, and the pores are mainly composed of micropore with a size of ca. 11.8 Å. This result agrees with the adsorption capacity obtained from water adsorption. According to diffuse reflectance ultraviolet-visible spectroscopy, it is found that the TiO2 particles stabilized in the interlayer space of montmorillonite are quantum-sized of ca. 20 Å.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.198-198
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• 2015

전기변색재료는 전압을 인가하였을 때 전계방향에 따라 가역적으로 색이 변화하는 재료를 말한다. 스마트윈도우용 전기 변색재료는 지속적으로 전기를 가해줄 필요 없이 한번 변색되면 색이 지속되는 특징을 가지므로 에너지 효율적으로 우수하여 태양열 차단 창호나 디스플레이 분야에 응용될 것으로 기대된다. 이러한 전기 변색재료에는 산화형 전기 변색 재료, 환원형 전기 변색 재료가 있는데 이중 가장 널리 연구되고 있는 재료는 환원형 전기변색재료이다. 대표적인 재료로 $WO_3$가 쓰이는 데 이는 전기 변색적 특성이 우수하고 또한 내구성이 다른 재료에 비해 우수하다는 장점 때문이다. 그러나, 상용화를 위해서는 내구성의 개선이 요구되고 있다. 한편, $TiO_2$는 안정성이 매우 뛰어나지만 전기변색적 특성이 $WO_3$에 비해 낮은 점이 지적되고 있다. 이러한 $WO_3$ 및 $TiO_2$ 박막은 스퍼터링 또는 sol-gel법 등으로 제작되고 있는데, 일반적으로 스퍼터링의 경우 치밀한 박막이 형성되기 때문에 Porous 한 박막을 얻기 힘들다. 따라서 본 연구에서는 기판에 입사하는 스퍼터 입자들의 각도를 조절하여 shadowing 효과로 인해 박막의 구조가 porous해지는 Glancing angle deposition을 도입하였다. 이러한 증착법을 이용하여 $WO_3$와 $TiO_2$를 각도를 조절하여 증착하고 $TiO_2$와 $WO_3$ 박막의 특성을 비교하여 본다. 두께 300 nm를 가지는 $WO_3$ 및 $TiO_2$ 박막은 GLAD RF 마그네트론 스퍼터링법을 이용하여 Corning glass(corning E-2000)기판 위에 증착하였다. 기판 입사 각도는 $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$로 증착하였고 직경 3 in의 $TiO_2$, $WO_3$ 타겟을 사용하였다. 또한 스퍼터링 파워는 400 W, 작업압력 1.0 Pa, 그리고 스퍼터링 가스는 O2/Ar+O2 유량 10%에서 30%로 증착을 상온에서 진행하였다. 전기화학적 특성을 평가하기 위하여 $TiO_2$ 및 $WO_3$ 박막을 100 nm 두께의 ITO/glass 위에서 증착하였다. 박막의 미세구조는 XRD와 SEM을 통해 확인하였고, 전기화학적 특성은 Ar 분위기의 Glove box안에서 parstat 2273을 통해 측정하였다. 전해질은 1 M $LiPF_6/PC$로 진행하였고, 대향 전극는 Pt전극을, 참고 전극은 칼로멜 전극을 사용하였다. Potential 범위는 2 V에서 4 V로 진행하였고, scan rate는 50 mV/s로 측정하였다. 투과도는 UV/VIS spectrometer로 측정하였다. 전기변색 특성의 상관관계 및 에 대해서는 학회 당일 발표할 예정이다.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1153-1157
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• 2002

The fabrication of a three-layered asymmetric ceramic membrane was performed by slip casting of the porous alumina support and dip coating of the alumina intermediate layer using high purity ${\alpha}-Al_2O_3$ powders that have different particle size, followed by screen printing-pyrolysis of the $Tio_2$ layer as an ultrafilteration membrane using Ti-naphthenate solution. The bending strength, porosity and mean pore size of the alumina support were 231 kg/$cm^2$s, 30.26% and 0.19 ${mu}m$, respectively. The thickness of the intermediate layer was 30 ${mu}m$ and the mean pore size of that was 0.063 ${mu}m$. Also, the top layer was 0.5 ${mu}m$ thick and micropores with about 20 nm size were formed uniformly.