• Title/Summary/Keyword: CNT paste

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Improvement of the Field Emission Stability of Carbon Nanotube Paste Emitter by Post-treatments

  • Choi, Young-Chul;Jeong, Mun-Seok
    • Carbon letters
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    • v.10 no.3
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    • pp.234-238
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    • 2009
  • The field emitters were fabricated by screen-printing of carbon nanotube paste, and their emission stabilities were evaluated. It was found that the emission stability measured in a sealed device is much higher than that measured in a vacuum chamber in spite of similar pressure. This was because oxygen gas was scarcely remained in the sealed device, while the gas is continuously supplied into the vacuum chamber during the stability measurement. It was found that the plasma treatment etched the protruded CNTs, resulting in the uniform height of CNT tips. As a result, the stability was increased remarkably. It was also found that the stability of CNT paste emitter was improved by electrical aging and that the optimum condition for the aging was varied with the size of emitter.

Field Emission properties of photosensitive carbon nanotube paste with different inorganic binders

  • Park, Jae-Hong;Moon, Jin-San;Jeong, Jin-Soo;Yoo, Ji-Beom;Park, Chong-Yun;Nam, Joong- Woo;Park, Jong-Hwan;Choe, Deok-Hyeon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1451-1454
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    • 2005
  • We report effects of inorganic binder on the emission properties of CNT paste for low cost and high low-cost and large area field emission devices or displays. Two types of photosensitive carbon nanotube (CNT) paste were formulated by using of glass frit and spin on glass (SOG) as an inorganic binder and investigated their emission properties according to inorganic binders and firing conditions.

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Electrochemical Properties of Carbon Nano-Tube Electrode (탄소나노튜브 전극의 전기화학적 특성)

  • Lee Dong-Yoon;Koo Bo-Kun;Lee Won-Jae;Song Jae-Sung;Kim Hyun-Ju
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.4
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    • pp.139-143
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    • 2005
  • For application of carbon nano-tube (CNT) as a counter electrode materials of dye-sensitized solar cell (DSSC), the electrochemical behavior of CNT electrode was studied, employing cyclic-voltammetry (C-V) and impedance spectroscopy. Fabrication of CNT-paste and formation of CNT-counter electrode for characteristic measurement have been carried out using ball-milling and doctor blade process, respectively. Unit cell for measurements was assembled using Pt electrode, CNT electrode, and iodine-embedded electrolyte. Field emission-scanning electron microscopy (FE-SEM) was used for structural investigation of CNT powder and electrode. Sheet resistance of electrode was measured with 4-point probe method. Electrochemical properties of electrode, C-V and impedance spectrum, were studied, employing potentiogalvanostat (EG&G 273A) and lock in amplifier (EG&G 5210). As a results, the sheet resistance of CNT electrode is almost similar to that of F-doped SnO2 (FTO) coated glass substrate as approximately 10 ohm/sq. From C-V and impedance spectroscopy measurements, it was found that CNT electrode has high reaction rate and low interface reaction resistance between CNT surface and electrolyte. These results provides that CNT electrode were superior to that of conventional Pt electrode. Particularly, the reaction rate in the CNT electrode is about thrice high than Pt electrode. Therefore. CNT electrode is to be good candidate material for counter electrode in DSSC.

Fabrication of CNT sensor to measure degradation of transformer (변압기 열화 상태 감지를 위한 CNT 샌서 제작)

  • Kim, Yong-Kook;Shin, Kyoung;Ju, Byeong-Kwon
    • Proceedings of the KIEE Conference
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    • 2008.05a
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    • pp.159-160
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    • 2008
  • 본 논문에서는 변압기 절연유 상태를 측정하여 변압기 열화정도를 분석할 수 있는 CNT센서를 개발하였다. 센서의 감지막 형성을 위해 MWCNT(multi walled carbon nanotube)로 CNT paste를 제작하고 이를 프린팅공정을 이용하여 그 규격을 최적화하였다. 제작된 CNT 센서를 이용하여 절연유 상태를 분석하고 이를 전기 화학적 분석을 통하여 변압기 열화 정도를 확인하였다. 변압기 사용 여부에 따른 센서의 특성과 절연유의 산가, 절연파괴전압 등 기타 특성과 비교하여 변압기 절연유의 열화정도를 확인하였다. 변압기 과부화 및 과전류에 의해 열화가 진행되어 전산가가 높아지면 이를 CNT 감지막의 전기적 특성 변화로 확인 할 수 있다. 개발된 IT 센서를 이용하면 변압기 열화 정도를 실시간으로 확인 할 수 있어 변압기 사용에 있어서 안정성 확보 및 유지관리에 경제성을 높일 수 있다.

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재열처리가 탄소나노튜브 캐소드의 전계방출 특성에 미치는 영향

  • Ha, Sang-Hun;Gwon, Na-Hyeon;Jang, Ji-Ho;Jo, Yeong-Rae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.446-446
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    • 2010
  • 탄소나노튜브(CNT, carbon nanotube)를 에미터 재료로 사용하여 전계방출 디스플레이 (FED, field emission display)용 캐소드(cathode)를 제작할 때 CNT paste를 구성하는 유기성 바인더를 제거하기 위한 열처리 공정은 필수적이며, 이후에 CNT의 돌출을 위한 표면처리 공정이 뒤따르게 된다. 이러한 표면처리에는 여러 가지 방법들이 있으며 캐소드 제작시 매우 중요한 부분이다. 그 이유는 열처리 과정을 거치게 되면 이물질들이 CNT를 감싸게 되는데 이는 전계방출을 방해하는 요소가 되기 때문에 이를 효과적으로 제거해주지 않으면 전계방출의 효율성이 떨어지기 때문이다. 본 연구는 스크린 인쇄법으로 제작한 CNT 캐소드의 표면처리에 관한 것으로 Tpae 방법을 이용하여 1차적으로 표면처리를 수행한 후 2차적으로 재열처리법을 이용하여 열처리 후 CNT를 감싸고 있는 이물질(ash, residue)등을 효과적으로 제거하였는지 전계방출 특성을 통하여 알아보았다.

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Effect of CNT Particle Dispersion in CNT Paste on Field Emission Characteristics in Carbon Nanotube Cathode (탄소나노튜브의 분산이 탄소나노튜브 캐소드의 전계방출 특성에 미치는 영향)

  • Ahn B. G.;Seung M. S.;Shin H. Y.;Kim D. H.;Kim T. S.;Cho Y. R.
    • Korean Journal of Materials Research
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    • v.14 no.11
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    • pp.807-812
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    • 2004
  • The uniformity of emission mage and field emission properties of carbon nanotube(CNT) cathodes dependence on CNT particle dispersion were investigated for field emission displays. We used multi-walled carbon nanotubes (MWNTs) synthesized by CVD method as the field emitter materials. CNT dispersion in CNT ink was carried out by ultrasonication and shaking methods. According to CNT dispersion conditions, the uniformity of emission image and field emission properties of CNT cathodes were greatly affected. The smaller particles of filler materials and CNT powders provide the better properties of the CNT cathodes.

Effects of Component Change of Bonding Materials on Field Emission Properties of CNT-Cathodes (본딩재료의 성분 변화가 탄소나노튜브 캐소드의 전계방출 특성에 미치는 영향)

  • Shin Heo-Young;Seong Myeong-Seok;Kim Tae-Sik;Oh Jeong-Seob;Jung Seung-Jin;Lee Ji-Eon;Cho Young-Rae
    • Korean Journal of Materials Research
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    • v.15 no.11
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    • pp.711-716
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    • 2005
  • The effects of change in the component of bonding materials in carbon nanotube cathode (CNT-cathode) on field enhancement and field emission characteristics were investigated. The field enhancement factor$\beta$ was dependent on the electrical conductivity of the bonding materials. The use of frit glass as a bonding material showed a higher field enhancement factor and better field emission characteristics than an Ag paste. The reason for why the frit glass showed better field emission characteristics can be summarized as follows. First, a frit glass improves the real aspect ratio of CNTs compared to an Ag paste. Second, the number of CNTs in CNT-cathodes is considerably reduced because the CNTs were extensively oxidized during $390^{\circ}C$ heat treatment in air atmosphere in the case of Ag paste.

Field Emission Characteristics of a CNT-FEA fabricated by Screen-printing of a Photo-sensitive CNT Paste (감광성 CNT 페이스트의 스크린 프린팅법을 이용한 CNT-FEA의 전계 방출 특성)

  • Kwon Sang-Jik;Lee Sang-Heon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.1
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    • pp.75-80
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    • 2006
  • We have fabricated a carbon nanotube field emission display(CNT-FED) panel with a 2 inch diagonal size using a screen printing method and in-situ vacuum sealing technology. The field emission properties of CNT FED panel with square-type CNT emitters. As results, the square-characterized and compared with those of the line-type CNT emitters. As results, the square-type CNT emitters showed much larger emission current and more stable I-V characteristics. Light emission started to be occurred at an electric field of 3.5 V/${\mu}m$ corresponding to the anode-cathode voltage of 700 V. The vacuum level inside of the in-situ vacuum sealed panel was obtained with $1.4 {\times} 10^{-5}$ torr. The sealed panel showed the similar I-V characteristics with the unsealed one and the uniform light emission with very high brightness at a current density of $243 {\mu}A/ cm^2$ obtained by the electric field of 10 V/${\mu}m$.

A Feasibility Study on Developing Snow Melting Systems using CNT-Cement Composite (도로 융설체 개발을 위한 탄소나노튜브-시멘트 복합체 특성에 관한 실험적 연구)

  • Heo, Jinnyung;Park, Bumjin;Kim, Taehyeong
    • International Journal of Highway Engineering
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    • v.15 no.2
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    • pp.29-37
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    • 2013
  • PURPOSES : This study aims to review the possibility of developing a road snow-melting system that can prevent slip accidents by maintaining a constant temperature of the winter roads and enhance performance of structures, including improvement of compressive strength by mixing carbon nanotube (hereafter referred to as CNT) with cement paste, the basic material. METHODS : To achieve the above purpose, an experiment was conducted by mixing power-type CNT and wrap-type CNT up to cement paste formulation by weight of 0.0wt%~4.1wt% in accordance with "KS L ISO 679(of cement strength test method)", and compressive strength was measured at 28 days of curing. In addition, the volume resistivity of the specimen was measured to test thermal and electrical characteristics, and the rate of temperature changes in specimen surface by power consumption was measured by passing electricity through the cross-sections of the specimen. Meanwhile, the criteria for checking the performance as a road snow-melting system was determined as volume resistivity of $100{\Omega}{\cdot}cm$ or less. RESULTS : A comparative analysis between specimen with 0wt% CNT content in plain status and specimen containing various types of CNTs was carried out. From its results, it was found that compressive strength increased approximately 19%, showing the highest rate when 0.2wt% of wrap-type CNT was contained, but volume resistivity of $100{\Omega}{\cdot}cm$ or less appeared only in specimens containing more than 0.2wt% CNT. In addition, it was observed that the surface temperature increased by $4.62^{\circ}C$ per minute on average in specimens containing 3.2wt% CNT. CONCLUSIONS : In this study, CNT was examined as an underlying material for a road snow-melting system, and the possibility of developing the road now-melting system was reviewed by conducting various experiments using CNT-Cement composites. From the experimental results, the specimens were found to have a superior performance when compared to the existing road snow-melting systems that place the heat transfer medium such as copper on the road. However, satisfactory strength performance were not obtained from the specimen containing CNT(2.0% or more) that functions as a heating element, which leads to the need for reviewing methods to increase the strength by using plasticizer or admixture.