• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.263-274
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• 1996

Titanium dioxide ($TiO_{2}$) film has been widely used as anti-reflection coating for solar cells but not as masking oxide for metallisation and diffusion of impurities. In this paper we have investigated the properties of $TiO_{2}$ for possible incorporation into solar cell processing sequence. Thus the use of a spray deposition system to form the $TiO_{2}$ film and the characterisation of this film to ascertain its suitability to solar cell processing. The spray-on $TiO_{2}$ film was found to be resistant to all the chemicals used in conjunction with solar cell processing. The high temperature anealing (in oxygen ambient) of the spray-on $TiO_{2}$ film resulted in an increased refractive index, which indicated the growth of an underlying thin film of $SiO_{2}$ film for the passivation of silicon surface which would reduce the recombination activities of the fabricated device. Most importantly, the successful incorporation of the $TiO{2}$ film will lead to the reduction of the many high temperature processing steps of solar cell to only one.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.192.1-192.1
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• 2016

타이타늄은 밸브 메탈의 일종으로, 다양한 전해질 조건에서 양극산화되어 이산화 타이타늄($TiO_2$)을 형성한다. 이산화 타이타늄은 저렴한 가격, 풍부함, 무독성, 높은 안정성 등 다양한 장점을 지닌다. 또한 리튬 이온의 삽입/탈리 이후에도 구조적인 변화가 적은 성질과 비교적 높은 방전 전압(1.0-2.5 V vs Li/Li+)으로 인해 그래파이트를 대체할 리튬이온 전지의 전극재료로써 연구되어 왔다. 하지만 낮은 이온 및 전기 전도도로 인해 다양한 분야에서의 활용에 한계가 있어왔다. 이러한 한계 극복을 위해, 이산화 타이타늄에 전도성이 높은 탄소 계열의 물질을 코팅하는 방법이 고려되었다. 그래핀 산화물은 강한 산을 이용하여 그래파이트를 산화시킨 물질로, 많은 산소작용기를 함유하고 있어 탄소 고유의 전기전도성을 갖지 못한다. 환원 그래핀 산화물(reduced graphene oxide)는 빛, 열, 화학 작용울 통해 그래핀 옥사이드를 환원시켜 산소작용기를 없앤 물질로, 환원과정에서 전기전도성을 회복한다. 이에 본 연구에서는 이산화 타이타늄에 환원 그래핀 산화물(reduced graphene oxide)를 코팅하여 전기 전도도를 향상시키고. 이에 대한 활용 분야를 연구하고자 하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.3
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• pp.223-229
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• 2013

Polymer Electrolyte Membrane Fuel Cell (PEMFC) is a power generation system to convert chemical energy of fuels and oxidants to electricity directly by electrochemical reactions. As a catalyst support for PEMFCs, carbon black has been generally used due to its large surface area and high electrical conductivity. However, under certain circumstances (start up/shut down, fuel starvation, ice formation etc.), carbon supports are subjected to serve corrosion in the presence of water. Therefore, it would be desirable to switch carbon supports to corrosion-resistive support materials such as metal oxide. $TiO_2$ has been attractive as a support with its stability in fuel cell operation atmosphere, low cost, commercial availability, and the ease to control size and structure. However, low electrical conductivity of $TiO_2$ still inhibits its application to catalyst support for PEMFCs. In this paper, to explore feasibility of $TiO_2$ as a catalyst support for PEMFCs, $TiO_2$ nanofibers were synthesized by electrospinning and calcinated at 600, 700, 800 and $900^{\circ}C$. Effects of calcination temperature on crystal structure and electrical conductivity of electrospun $TiO_2$ nanofibers were examined. Electrical conductivity of $TiO_2$ nanofibers increased significantly with increasing calcination temperature from $600^{\circ}C$ to $700^{\circ}C$ and then increased gradually with increasing the calcination temperature from $700^{\circ}C$ to $900^{\circ}C$. It was revealed that the remarkable increase in electrical conductivity could be attributed to phase transition of $TiO_2$ nanofibers from anatase to rutile at the temperature range from $600^{\circ}C$ to $700^{\circ}C$.