Fully Flexible MXene-based Gas Sensor on Paper for Highly Sensitive Room-Temperature Nitrogen Dioxide Detection

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Flexible chemiresistive gas sensors are crucial for real-time gas detection but face performance limitations due to poor electrode-semiconductor charge transfer.
• Conventional metal electrodes often lead to inefficient charge transfer in flexible gas sensing devices.

Purpose of the Study:

• To develop a fully flexible, paper-based gas sensor with improved performance for gas detection.
• To investigate the use of MXene-based electrodes and novel sensing films for enhanced charge transfer and sensing capabilities.

Main Methods:

• Fabrication of a flexible paper-based gas sensor integrating Ti3C2Tx-MXene nonmetallic electrodes with a Ti3C2Tx/WS2 gas sensing film.
• Characterization of the sensor's response to NO2 at room temperature.
• Utilizing first-principles density functional theory (DFT) calculations to understand performance enhancement mechanisms.

Main Results:

• The developed sensor demonstrated a significant response of 15.2% to 1 ppm NO2 at room temperature, outperforming traditional gold electrodes.
• Achieved a low limit of detection of 11.0 ppb for NO2 gas with excellent stability under high humidity.
• DFT calculations revealed that heterojunction regulation, work function matching, and suppressed metal-induced gap states contribute to improved sensing performance.

Conclusions:

• The integration of Ti3C2Tx-MXene electrodes and Ti3C2Tx/WS2 sensing films provides an effective strategy for creating high-performance flexible gas sensors.
• This novel design offers a promising pathway for developing advanced, paper-based gas sensors with superior charge transfer and detection capabilities.