• Electrical & Electronic Materials
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• v.10 no.3
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• pp.233-238
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• 1997

We have investigated gas-detection characteristics of CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices exposed to air/200ppm N $O_{2}$ gases. The CuTBP films were made by Langmuir-Blodgett (LB) techniques. Sensitivity, response time, recovery time, and reproducibility of the devices were measured by current voltage characteristics. Interdigital electrode was used to improve the sensitivity. It was observed that a conductance G increases monotonically as the number of interdigital electrode finger pairs increases. As the number of interdigital electrode finger pairs increases, the sensitivity S( $G_{gas}$/ $G_{air}$) increases more than 50 times and stable. But the response time was delayed. The average recovery time of the CuTBP chemiresistor devices turned out to be about 100 second. We have also investigated applicability of the CuTBP chemiresistor device for a gas sensor.sor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.417-420
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• 1996

We have investigated air/200ppm NO$_2$ gas-detector characteristics of using CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices. The CuTBP films were made by Langmuir-Blodgett (LB) techniques. Sensitivity, response time, recovery time, and repoducibility of the devices were measured by current-voltage characteristics. To increase sensitivity, interdigital electrode was used. It was found that a conductance G increases monotonically as the number of interdigital electrode increases, and a Sensitivity, Reproducibility is stable. As far as a current is concerned, the current when N=25 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrodes affects the current, sensitivity and stability We have also investigated applicability of the CuTBP chemiresistor device for a gas detector.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.6.2-8
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• 1996

The NO$_2$ GAS-detection characteristic of CuTBT (Copper-tetra-tert-butylphtha1ocyanine) LB films were investigated through a study of current-voltage (I-V) characteristics with a variation of number N of interdigital electrodes (N=1∼25). A concentration of 200ppm NO$_2$ gas was used. It was found that a conductance G increases monotonically as the number of interdigital electrode increases, and a sensitivity $\Delta$G ($\Delta$G=G$\_$gas//G$\_$air/) is at least higher than 50 and stable. As far as a sensitivity is concerned, the sensitivity when N=26 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrodes affects the currents, sensitivity and stability.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.51.3-51.3
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• 2010

Due to the recent public awareness of global warming and sustainable economic growth, there has been a growing interest in alternative clean energy sources. Hydrogen is considered as a clean fuel for the next generation. One of the technical challenges related to the use of hydrogen is safe monitoring of the hydrogen leak during separation, purification and transportation. For detecting various gases, chemiresistor-type gas sensors have been widely studied and used due to their well-established detection scheme and low cost. However, it is known that many of them have the limited sensitivity and slow response time, when used at low temperature conditions. In our work, a sensor based on Schottky barriers at the electrode/sensing material interface showed promising results that can be utilized for developing fast and highly sensitive gas sensors. Our hydrogen sensor was designed and fabricated based on indium oxide (In2O3)-doped tin oxide (SnO2) semiconductor nanoparticles with platinum (Pt) nanoclusters in combination with interdigitated electrodes. The sensor showed the sensitivity as high as $10^7%$ (Rair/Rgas) and the detection limit as low as 30 ppm. The sensor characteristics could be obtained via optimized materials synthesis route and sensor electrode design. Not only the contribution of electrical resistance from the film itself but also the interfacial effect was identified as an important factor that contribute significantly to the overall sensor characteristics. This promises the applicability of the developed sensor for monitoring hydrogen leak at room temperature.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2867-2872
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• 2012

SAN/$BMIPF_6$ nanofibers were fabricated by an electrospinning process and used as chemiresistors for sensing alcohol vapours. A hydrophobic and air-stable ionic liquid, $BMIPF_6$, was used to impart electrical conductivity to insulating SAN nanofibers. The effects of $BMIPF_6$ addition on the morphology of the nanofibers were explained in terms of surface tension, viscosity and conductivity. After exposing the SAN/$BMIPF_6$ nanofibers collected on an interdigitated electrode to alcohol vapours (ethanol, 1-propanol and 1-butanol), the resistance of the nanofibers decreased due to adsorption of alcohol molecules. The electrospun SAN/$BMIPF_6$ nanofibers sensor exhibited good sensitivity and reproducibility.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.25.2-25.2
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• 2011

The tungsten oxide wire-like nanostructure is fabricated by deposition and thermal oxidation of tungsten metal on porous single wall carbon nanotubes (SWNTs). The morphology and crystalline quality of materials are investigated by SEM, TEM, XRD and Raman analysis. The results prove that $WO_3$ wire-like nanostructure fabricated on SWNTs show highly porous structures. Exposure of the sensors to NH3 gas in the temperature range of 150~300$^{\circ}C$ resulted in the highest sensitivity at $250^{\circ}C$ with quite rapid response and recovery time. Response time as a function of test concentrations and NH3 gas sensing mechanism is reported and discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.288-293
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• 2017

$Fe_2O_3$ is one of the most important metal oxides for gas sensing applications because of its low cost and high stability. It is well-known that the shape, size, and phase of $Fe_2O_3$ have a significant influence on its sensing properties. Many reports are available in the literature on the use of $Fe_2O_3$-based sensors for detecting gases, such as $NO_2$, $NH_3$, $H_2S$, $H_2$, and CO. In this paper, we investigated the gas-sensing performance of a Pt-doped ${\varepsilon}$-phase $Fe_2O_3$ gas sensor. Pt-doped $Fe_2O_3$ nanoparticles were synthesized by a Sol-Gel method. Platinum, known as a catalytic material, was used for improving gas-sensing performance in this research. The gas-response measurement at $300^{\circ}C$ showed that $Fe_2O_3$ gas sensors doped with 3%Pt are selective for $NO_2$ gas and exhibita maximum response of 21.23%. The gas-sensing properties proved that $Fe_2O_3$ could be used as a gas sensor for nitrogen dioxide.