• Title/Summary/Keyword: CNT cathode

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The effects of conductivity and CNT cathode on electricity generation in air-cathode microbial fuel cell (공기양극 미생물연료전지 시스템에서 전력발생특성에 미치는 전기전도도와 CNT 양극의 영향)

  • Yoo, Kyu-Seon;Park, Hyun-Soo;Song, Young-Chae;Woo, Jung-Hui;Lee, Chae-Young;Chung, Jae-Woo
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.3
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    • pp.355-360
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    • 2012
  • The characteristics of power generation were investigated by changing the electrical conductivity from 10 to 40mS/cm using air-cathode microbial fuel cell, which had graphite fiber fabric(GFF) anode. There were three kinds of cathode used: one was carbon cloth cathode coated with Pt, another was carbon nanotube(CNT) cathode with non-precious catalyst of Fe-Cu-Mn, and the other was carbon nanotube(CNT) cathode without any catalyst. When it was operated in batch mode, power density of 1369.5mW/$m^2$ was achieved at conductivity of 20mS/cm. Power density from MFC with CNT cathode coated with multi-catalyst of Fe-Cu-Mn was shown about 985.55mW/$m^2$, which was 75.1% compared the power density of carbon cloth coated with Pt. This meant that CNT cathode coated with multi-catalyst of Fe-Cu-Mn could be an alternative of carbon cloth cathode.

Low Voltage-Driven CNT Cathode and It's Applications

  • Lee, Chun-Gyoo;Lee, Sang-Jo;Cho, Sung-Hee;Chi, Eung-Joon;Lee, Byung-Gon;Jeon, Sang-Ho;Ahn, Sang-Hyuck;Hong, Su-Bong;Choe, Deok-Hyeon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.851-854
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    • 2004
  • By approaching the counter electrode to the CNT emitter, remarkable reduction of the cathode operating voltage has been accomplished in the under-gate CNT cathode structure. The peak emission current density of 2.5 ms/$cm^2$, which is sufficient for high brightness CNT field emission display, was obtained at the cathode-to-gate voltage of 57 V when the CNT-to-counter electrode gap was 2.2 ${\mu}m$. The gate current was less than 10 % of the anode current. The CNT cathode with low driving voltage can help the cost-effective field emission display implemented.

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Effect of Nano-Sized Silver Powders in CNT Paste on Field Emission Characteristics of Carbon Nanotube Cathode (탄소나노튜브 캐소드의 전계방출 특성에 미치는 CNT 페이스트용 나노입자 은분말의 영향)

  • An, Young-Je;Lee, Ji-Eon;Shin, Heon-Cheol;Cho, Young-Rae
    • Korean Journal of Materials Research
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    • v.18 no.1
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    • pp.12-17
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    • 2008
  • Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver (Ag) powders as a bonding material between the CNTs and cathode electrodes. The effects of the powder size on the sintering behavior, the current density and emission image for CNT cathodes were investigated. As the diameter of the Ag powders decreases to 10 nm, the sintering temperature of the CNT cathode was lowered primarily due to the higher specific surface area of the Ag powders. In this study, it was demonstrated that nano-sized Ag powders can be feasibly used as a bonding material for a screen-printed CNT cathode, yielding a high current density and a uniform emission image.

Effects of Materials Composition in CNT Paste on Field Emission Properties in Carbon Nanotube Cathodes (인쇄용 페이스트의 조성변화가 탄소나노튜브 캐소드의 전계방출 특성에 미치는 영향)

  • Choi, Woo-Suk;Shin, Heo-Young;Kim, Dong-Hee;Ahn, Byung-Gun;Chung, Won-Sub;Lee, Dong-Gu;Cho, Young-Rea
    • Korean Journal of Materials Research
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    • v.13 no.10
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    • pp.663-667
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    • 2003
  • The effects of paste materials on field emission properties in a carbon nanotube(CNT) cathode were investigated for high-efficient field emission displays. The major components in CNT paste for screen printing were a metallic Ag-paste, a dielectric glass-frit and CNT ink. The emission current from the cathode by an electron tunneling effect increased with an increase in the dielectric material fraction in the CNT paste, which is related to an increase of field enhancement factor in Fowler-Nordheim equation. The surface treatment used, after soft baking of the screen-printed CNT films, greatly affected the decrease in the turn-on field in CNT cathode and the uniformity of emission sites over the entire CNT film area.

Development of Two-Step Surface Treatment on Carbon Nanotube Cathode for Backlight Unit Application

  • Ha, Sang-Hoon;Jung, Dea-Hwa;Park, Ki-Jung;Kwon, Na-Hyun;Choi, Young-Jun;Chang, Ji-Ho;Cho, Young-Rae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.152-155
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    • 2009
  • A novel two-step surface treatment was developed and demonstrated for the carbon nanotube (CNT) cathode with highly efficient backlight unit application. An adhesive taping method was applied firstly and then followed by a post-heat treatment for the CNT cathode. During the postheat treatment process, some residues covering the CNTs were burned out. The post-heat treatment enhanced the emission current of the CNT cathode around 20% compared with that of no heat-treated sample.

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Actively Addressable Carbon NanoTube Emitters for Field Emission Display

  • Song, Yoon-Ho;Hwang, Chi-Sun;Kim, Kwang-Bok
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.194-197
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    • 2003
  • The actively addressable carbon nanotube (CNT) emitters have been studied for stable and low-voltage driving field emission display (FED). The a-Si TFT and screen-printed CNT emitters were successfully integrated to fabricate the diode type active-matrix cathode and FED panel. Also, we propose a new FED architecture based on the actively controlled triode CNT emitters showing the properties of ideal triode type cathode with electron beam focusing effect.

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Effect of Liquid Surface Treatments on Field Emission Properties of Carbon Nanotube Cathodes

  • Lee, Ji-Eon;An, Young-Je;Shin, Heon-Cheol;Chung, Won-Sub;Cho, Young-Rae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.486-489
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    • 2007
  • Carbon nanotube (CNT) cathodes having a trench structure similar to the structure of the gated triodetype cathode were successfully fabricated by a screenprinting method with multi-walled carbon nanotubes. We observed that a liquid method not only readily removes the organic residues on the CNT films, but also satisfactorily protrudes the CNTs out of the electrode surface. The CNT cathodes prepared by the liquid method showed a turned-on field of $1.4\;V/{\mu}m$. The emission current density of them was about $3.1\;mA/cm^2$ at the electric field of $3\; V/{\mu}m$. The liquid method appears to be a promising surface treatment of CNT cathode for gated triode-type FEDs applications.

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Fabrication of Field Emitter Arrays by Transferring Filtered Carbon Nanotubes onto Conducting Substrates

  • Jang, Eun-Soo;Goak, Jung-Choon;Lee, Han-Sung;Lee, Seung-Ho;Lee, Nae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.311-311
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    • 2009
  • Carbon nanotubes (CNTs) belong to an ideal material for field emitters because of their superior electrical, mechanical, and chemical properties together with unique geometric features. Several applications of CNTs to field emitters have been demonstrated in electron emission devices such as field emission display (FED), backlight unit (BLU), X-ray source, etc. In this study, we fabricated a CNT cathode by using filtration processes. First, an aqueous CNT solution was prepared by ultrasonically dispersing purified single-walled CNTs (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). The aqueous CNT solution in a milliliter or even several tens of micro-litters was filtered by an alumina membrane through the vacuum filtration, and an ultra-thin CNT film was formed onto the alumina membrane. Thereafter, the alumina membrane was solvated by acetone, and the floating CNT film was easily transferred to indium-tin-oxide (ITO) glass substrate in an area defined as 1 cm with a film mask. The CNT film was subjected to an activation process with an adhesive roller, erecting the CNTs up to serve as electron emitters. In order to measure their luminance characteristics, an ITO-coated glass substrate having phosphor was employed as an anode plate. Our field emitter array (FEA) was fairly transparent unlike conventional FEAs, which enabled light to emit not only through the anode frontside but also through the cathode backside, where luminace on the cathode backside was higher than that on the anode frontside. Futhermore, we added a reflecting metal layer to cathode or anode side to enhance the luminance of light passing through the other side. In one case, the metal layer was formed onto the bottom face of the cathode substrate and reflected the light back so that light passed only through the anode substrate. In the other case, the reflecting layer coated on the anode substrate made all light go only through the cathode substrate. Among the two cases, the latter showed higher luminance than the former. This study will discuss the morphologies and field emission characteristics of CNT emitters according to the experimental parameters in fabricating the lamps emitting light on the both sides or only on the either side.

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Effects of Surface Treatment on Field Emission Properties for Carbon Nanotube Cathodes (탄소나노튜브 캐소드에서 표면처리 방법이 전계방출 특성에 미치는 영향)

  • Seong, Myeong-Seok;Oh, Jeong-Seob;Lee, Ji-Eon;Jung, Seung-Jin;Kim, Tae-Sik;Cho, Young-Rae
    • Korean Journal of Materials Research
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    • v.16 no.1
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    • pp.37-43
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    • 2006
  • Carbon nanotube cathodes (CNT cathodes) were fabricated by a screen printing method using multi-walled carbon nanotubes. The effects of surface treatment on CNT cathodes were investigated for use in high efficiency field emission displays. The optimum surface treatment for a CNT cathode is dependent on a relative bonding force of CNT films on the cathode after a heat treatment. Because of the high bonding force used in the Liquid method, this method is recommended for CNT cathodes which are heat-treated at $390^{\circ}C$ in a $N_2$ atmosphere. The Rolling method is applicable for CNT cathodes fabricated at $350^{\circ}C$ in an atmosphere of air. The results of this study provide basic criteria for the selection of an appropriate surface treatment for large area CNT cathodes.

A X-ray Tube Using Field Emitter Made by Multi-walled Carbon Nanotube Yarns

  • Kim, Hyun-Suk;Castro, Edward Joseph D.;Kwak, Seung-Im;Ju, Jin-Young;Hwang, Yong-Gyoo;Lee, Choong-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.392-392
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    • 2011
  • Carbon nanotubes (CNT) emitter has widely become an attractive mechanism that draws growing interests for cold cathode field emission.$^{1,2}$ CNT yarns have demonstrated its potential as excellent field emitters.$^3$ Extensive simulations were carried out in designing a CNT yarn-based cathode assembly. The focal spot size dependence on the anode surface of the geometric parameters such as axial distance of the electrostatic focus lens from the cathode and the applied bias voltages at the cathode, grid mesh and electrostatic focus lens were studied. The detailed computer simulations using Opera 3D electromagnetic software$^4$ had revealed that a remarkable size of focal spot under a focusing lens triode type set-up design was achieved. The result of this optimization simulation would then be applied for the construction of the CNT yarn based micro-focus x-ray tube with its field emission characteristics evaluated.

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