Role of en-APTAS Membranes in Enhancing the NO<sub>2</sub> Gas-Sensing Characteristics of Carbon Nanotube/ZnO-Based Memristor Gas Sensors

NO<sub>2</sub> is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO<sub>2</sub> is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising material...

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Bibliographic Details
Main Authors: Ibtisam Ahmad, Mohsin Ali, Hee-Dong Kim
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Biosensors
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Online Access:https://www.mdpi.com/2079-6374/14/12/635
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Summary:NO<sub>2</sub> is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO<sub>2</sub> is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising materials for NO<sub>2</sub> gas sensors due to their excellent electronic properties and high adsorption energy for NO<sub>2</sub> molecules. However, conventional CNT-based sensors face challenges, including low responses at room temperature (RT) and slow recovery times. This study introduces a memristor-based NO<sub>2</sub> gas sensor comprising CNT/ZnO/ITO decorated with an N-[3-(trimethoxysilyl)propyl] ethylene diamine (en-APTAS) membrane to enhance room-temperature-sensing performance. The amine groups in the en-APTAS membrane increase adsorption sites and boost charge transfer interactions between NO<sub>2</sub> and the CNT surface. This modification improves the sensor’s response by 60% at 20 ppm compared to the undecorated counterpart. However, the high adsorption energy of NO<sub>2</sub> slows the recovery process. To overcome this, a pulse-recovery method was implemented, applying a −2.5 V pulse with a 1 ms width, enabling the sensor to return to its baseline within 1 ms. These findings highlight the effectiveness of en-APTAS decoration and pulse-recovery techniques in improving the sensitivity, response, and recovery of CNT-based gas sensors.
ISSN:2079-6374