• Archives of Metallurgy and Materials
• /
• v.65 no.3
• /
• pp.1011-1014
• /
• 2020

Ice formed on radome surfaces causes communication disruption due to radio-frequency interference (RFI), which reveals the importance of de-icing systems for radomes. As a radome de-icing application, in this work, carbon nanotube (CNT) thin films were fabricated using a spray-coating method, and influence of process parameters on RF transmittance and electrothermal properties was investigated. With the increase of spraying time, sheet resistance of the fabricated film decreases, which results in a decrease of the RF transmittance and improvement of the heating performance. Also, the de-icing capability of the fabricated CNT film was evaluated at -20℃, and efficient removal of ice under cold conditions was demonstrated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.156-157
• /
• 2006

To improve mean-life and reliability of power cable in this study, we have investigated chemical properties showing by changing the content of Carbon nanotube(CNT) that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the three of existing resins and the five of specimens for measurement. Chemical properties of specimens was measured by FT-ATR (Fourier Transform Attenuated Total Reflectance). The condition of specimens was a solid sheet. We could observe functional group (C=O, carbonyl group) of specimens through FT-ATR. From these experimental result, the concentration of functional group (C=O) was high according to increasing the content of Carbon nanotube. We could know CNT/EEA was excellent more than other specimens from above experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.416-417
• /
• 2007

We prepared flexible transparent conducting electrodes by spray coating of single-walled carbon nanotube (SWNT) networks on PET substrate and have demonstrated their use as transparent anodes for flexible organic light emitting diodes (OLEDs). The flexible CNT electrode produced by spray coating method shows relatively low sheet resistance ($150{\sim}220{\Omega}/sq.$) and high transmittance of ~60% even though it was prepared at room temperature. In addition, CNT electrode/PET sample exhibits little resistance change during 2000 bending cycles, demonstrated good mechanical robustness. Using transparent CNT electrode, it is readily possible to achieve performances comparable to commercial ITO-based OLEDs. This indicates that flexible CNT electrode is alternative anode materials for conventional ITO anode in flexible OLEDs.

• Journal of Industrial Convergence
• /
• v.20 no.10
• /
• pp.33-38
• /
• 2022

In this paper, a simple method of forming a solution-based carbon nanotube (CNT) for use as a conductive material for electronic devices was studied. The CNT thin film coating was performed on the glass by applying the spin coating method and the argon atmospheric pressure plasma process. In order to observe changes in electrical and physical properties according to the number of coatings, samples formed in the same manner from times 1 to 5 were prepared, and surface shape, reflectance, transmittance, absorbance, and sheet resistance were measured for each sample. As the number of coatings increased, the transmittance decreased, and the reflectance and absorptivity increased in the entire measurement wavelength range. Also, as the wavelength decreases, the transmittance decreases, and the reflectance and absorption increase. In the case of electrical properties, it was confirmed that the conductivity was significantly improved when the second coating was applied. In conclusion, in order to replace CNT with a transparent electrode, it is necessary to consider the number of coatings in consideration of reflectivity and electrical conductivity together, and it can be seen that 2 times is optimal.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.136-136
• /
• 2003

카본나노튜브는 상용되는 기존의 센서에 비해 표면적이 넓어 감도가 놀고 응답속도가 빠르다. 또한 나노 스케일의 크기를 가지므로 고직접화를 실현할 수 있으며 기능복구성이 뛰어나 상온동작을 통한 저전력화가 가능하다. 본 실험에서는 아크방전법으로 합성한 카본나노튜브를 가스센서로 제작하여 상온에서 NH$_3$, NO 가스와의 반응 특성을 평가하였다. 또한 origin soot와 이를 정제한 purified CNT를 SEM(주사전자현미경), TEM(투과전자현미경), Raman scattering spectroscopy(라만 산란 분광기)를 통해 재료적 특성을 조사하고 이를 가스 감응 곡선과 연관하여 비교, 분석하였다. 전극에 CNT막을 형성시키기 위해 3g의 N,N dimethylformamide 용액에 CNT 10mg을 분산시킨 후 2시간동안 초음파 처리하였다. 이 용액을 mask를 이용해 전극 위에 막을 형성시킨 후 20$0^{\circ}C$에서 열처리하였다. 이렇게 제조된 origin soot와 purified CNT센서는 flow system을 이용하여 측정하였고 $N_2$분위기 하에서 센서를 안정화시킨 후 측정가스와의 반응을 살펴보았다 센서의 반응속도, 회복속도, 감도 등의 측정결과 origin soot는 NH$_3$ 25ppm에서 20%, purified CNT는 1%의 감도를 보여 20배 높은 감도를 보았다. NO 25ppm의 경우에도 origin soot가 8%, purified CNT는 0.8%의 감도를 보여 10배 높은 감도를 보였다. 이는 탄소입자가 많은 origin soot가 purified CNT 보다 표면적이 넓어 보다 많은 가스 흡착 싸이트를 가지기 때문이다. 하지만 origin soot는 반응시간과 회복속도가 Purified CNT 보다 2배 이상 느려 표면적 증가에 따른 가스 흡착과 탈착 능력이 떨어짐을 알 수 있었다. 또한 CNT와 가스사이의 전하 이동 방향에 따라 NH$_3$는 양의 감도를 NO는 음의 감도를 보였다 이는 전하의 이동 방향에 따라 전하와 캐리어 사이의 결합 및 해리가 일어나게 되고 결국 카본나노튜브 내의 캐리어 수를 증감시킴에 따라 나타나는 현상이다. 이러한 가스의 감도는 농도에 따라 증가하였으며 origin soot를 이용하여 1ppm이하의 NH$_3$ 가스를 검출할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.77-77
• /
• 2007

The development of next generation displays such as flexible display is a major challenge. Most materials and processes in current flat panel display industry cannot be transferred to flexible substrates. Typically, indium tin oxide (ITO) thin films are brittle and need to be deposited at high temperature to achieve an optimal opto-electrical property, therefore ITO films cannot be used as a flexible electrode. Up to date, many alternative materials to ITO have been proposed such as conductive polymers, nanometals, solution deposited transparent conductive oxide(TCO) and carbon nanotubes(CNTs). CNT based transparent conductive films are fabricated on glass and polymer substrates. CNT thin films exhibit a sheet resistance ($R_s$) of nearby $10^3\;{\Omega}/sq$ with a transmittance of around 80% on the visible light range, which is attributed by excellent dispersion and interaction among CNTs, solvents and polymeric binders. This talk will present the current studies, opto-electrical properties, design criteria and its applications for CNT-based transparent conductive films.

• Clean Technology
• /
• v.28 no.4
• /
• pp.278-284
• /
• 2022

This study presents an excellent planar heater based on low-dimensional composites. By optimizing the ratio of 1D carbon nanotubes (CNT) and 2D MXene (Ti₃C₂T_X), it is possible to create a planar heater that has superior electrical conductivity and high heat generation characteristics. Low-dimensional composites were prepared by mixing CNT paste and MXene solution with eco-friendly waterborne polyurethane (WPU). In order to find the optimal mixing ratio for the MXene-CNT-WPU composites, samples with MXene to CNT weight ratios of 3:1, 1:1, 1:3, 1:7, and 1:14 were investigated. In addition to these different weight ratios, 5 wt% WPU was equally applied to each sample. It was confirmed that the higher the weight ratio of CNT, the lower the sheet resistance and the higher the heating temperature. In particular, when the MXene-CNT-WPU planar heater was fabricated by mixing MXene and CNT at a weight ratio of 1:7 and 1:14, the heating temperature was higher than the heating temperature of a CNT-WPU planar heater. These characteristics are due to the optimized mixture of the 1D materials (CNT) and the 2D materials (MXene) causing the formation of a flat surface and a dense network structure. The low-dimensional composites manufactured with the optimized mixing ratios found in this study are expected to be applied in flexible electronic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.6
• /
• pp.451-455
• /
• 2012

To compare an electrical and optical characteristics of indium tin oxide (ITO) and carbon nanotube (CNT) electrode on flexible and reflective display, we fabricate two charged particle-type display panels under the same panel condition of which the width of ribs is 10 ${\mu}m$, the cell size is $300{\mu}m{\times}300{\mu}m$, the q/m value of the white particles is -4.3 ${\mu}C/g$ and that for the black is +1.3 ${\mu}C/g$, and the cell gap is 75 ${\mu}m$, 125 ${\mu}m$, and 175 ${\mu}m$. We use plastic substrates coated with ITO and CNT electrode. To evaluate optical property, we measure a response time of particles using a laser and a photodiode. Threshold and driving voltages of CNT electrode according to the sheet resistance of 300, 600, 1,000 (ohm/sq) are compared with ITO electrode of 10 (ohm/sq). A response time of the CNT panel is similar to that of ITO panel, but the threshold and driving voltages of CNT panel are higher than that of ITO panel, inducing a large bombardment of the particles and shortening the lifetime of the panel. High difference of a threshold and a driving voltage of CNT panel will induce an particle clumping, resulting degradation of the panel. A bending radius of the fabricated CNT panel is 18 ${\mu}m$.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.11
• /
• pp.514-519
• /
• 2006

To improve the mean-life and the reliability of power cable, we have investigated specific heat (Cp) and thermal conductivity of XLPE insulator and semiconducting materials in 154[kV] underground power transmission cable. Specimens were made of sheet form with the seven of specimens for measurement. Specific heat (Cp) and thermal conductivity were measured by DSC (Differential Scanning Calorimetry) and Nano Flash Diffusivity. Specific-heat measurement temperature ranges of XLPE insulator were from $20[^{\circ}C]\;to\;90[^{\circ}C]$, and the heating rate was $1[^{\circ}C/min]$. And the measurement temperatures of thermal conductivity were $25[^{\circ}C],\;55[^{\circ}C]\;and\;90[^{\circ}C]$. In case of semiconducting materials, the measurement temperature ranges of specific heat were from $20[^{\circ}C]\;to\;60[^{\circ}C]$, and the heating rate was $1[^{\circ}C/min]$. And the measurement temperatures of thermal conductivity were $25[^{\circ}C]\;and\;55[^{\circ}]C$. From these experimental results both specific heat and thermal conductivity were increased by heating rate because volume of materials was expanded according to rise in temperature. We could know that a small amount of CNT has a excellent thermal properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.10
• /
• pp.1090-1094
• /
• 2004

Studies on porous oxide electrode, dye and electrolyte for dye-sensitized solar cells have been intensively carried out until now. However, counter electrode have not been much studied so far. Accordingly, it is needed to investigate new counter electrode materials with superior catalyst property and to substitute for Pt electrode. In this case, carbon nano-tubes (CNTs) are one of alternatives for counter electrodes as following merits: low resistivity, excellent electron emission property, large surface area and low cost due to development of mass production technique. Such advantages gave us to select multiwalled CNTs (MWCNT) as counter electrode for dye-sensitized solar cell. Also, cyclic voltammetry and impedance spectroscopy were used to investigate electrochemical properties of both CNT electrode and Pt electrode. It was found that sheet resistance of CNT electrode was similar to that of Pt electrode, also, electrochemical properties of CNT electrode was superior to that of Pt electrode on the basis on the measurement of CV and impedance spectrum. It was found that CNT is likely to be a very promising electrode material for dye solar cells.