• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.274-287
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• 2024

Chemiresistors play a crucial role in numerous research fields, including environmental monitoring, healthcare, and industrial safety, owing to their ability to detect and quantify gases with high sensitivity and specificity. This review provides a comprehensive overview of the recent advancements in photoactivated chemiresistors and emphasizes their potential for the development of highly sensitive, selective, and low-power gas sensors. This study explores a range of structural configurations of sensing materials, from zero-dimensional quantum dots to three-dimensional, porous nanostructures and examines the impact of these designs on the photoactivity, gas interactions, and overall sensor performance-including gas responses and recovery rates. Particular focus is placed on metal-oxide semiconductors and the integration of ultraviolet micro-light emitting diodes, which have gained attention as key components for next-generation sensing technologies owing to their superior photoactivity and energy efficiency. By addressing existing technical challenges, such as limited sensitivity, particularly at room temperature (~22℃), this paper outlines future research directions, highlighting the potential of photoactivated chemiresistors in developing high-performance, ultralow-power gas sensors for the Internet of Things and other advanced applications.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.4
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• pp.528-534
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• 2024

In continuous research of detecting highly toxic chemical warfare agents to ensure preparedness for the future battlefield, flexible and wearable sensor platforms with high sensitivity are still demanding. Herein we demonstrate a facile fabrication of polypyrrole-based chemiresistors on cellulose paper for the detection of nerve gas simulants. In order to optimize electrical properties of sensor platform, conducting polymer made of polypyrrole were first synthesized on flexible cellulose paper and interdigitated electrodes were formed thereon. Following confirmation of polypyrrole and/or oxime moiety through FT-IR analyses, electrical characteristics were measured in the various ratio of monomers between simple pyrrole and oxime-modified one. Typically for the optimized chemiresistor(2:8 molar ratio of simple pyrrole and oxime-modified one), eleven species of chemical warfare agents were examined and enhanced conductivity(10⁴~10⁵ order) was observed for three simulants(diethyl cyanophosphonate, diisopropyl fluorophosphonate and diethyl chlorophosphonate), which was mainly attributed to intermolecular hydrogen bonding, while no significant responses was recorded against sixteen common volatile organic chemicals.

• Journal of Sensor Science and Technology
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• v.22 no.1
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• pp.1-17
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• 2013

Metal oxides designed for application in conductometric gas sensors and approaches used for synthesis of metal oxides with improved gas sensing characteristics are discussed in present article.

• 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.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.48-55
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• 2024

Metal-oxide-based semiconductor gas sensors are widely used because of their advantages, such as high response and simple sensing mechanism. Recently, with the rapid progress in sensor networks, computing power, and microsystem technology, sensor applications are expanding to various fields, such as food quality control, environmental monitoring, healthcare, and artificial olfaction. Therefore, the development of highly selective gas sensors is crucial for practical applications. This article reviews the developments in novel sensor design consisting of sensing films and physical and chemical filters for highly selective gas sensing. Unlike conventional sensors, the sensor structures with filters can separate the sensing and catalytic reactions into independent processes, enabling selective and sensitive gas sensing. The main objectives of this study are directed at introducing the role of various filters in gas-sensing reactions and promising sensor applications. The highly selective gas sensors combined with a functional filter can open new pathways toward the advancement of high-performance gas sensors and electronic noses.