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

Abstract

Flexible chemiresistive gas sensors have attracted growing interest due to their capability in real-time and rapid detection of gas. However, the performance of gas sensors has long been hindered by the poor charge transfer ability between the conventional metal electrode and gas sensing semiconductors. Herein, for the first time, a fully flexible paper-based gas sensor integrated with the Ti 3 C 2 T x -MXene nonmetallic electrode and the Ti 3 C 2 T x /WS 2 gas sensing film was designed to form Ohmic contact and Schottky heterojunction in a single gas sensing channel. Ti 3 C 2 T x /WS 2 has outstanding physical and chemical properties for both Ti 3 C 2 T x and WS 2 nanoflakes, showing high conductivity, effective charge transfer, and abundant active sites for gas sensing. The response of the gas sensor to NO 2 (1 ppm) at room temperature is 15.2%, which is about 3.2 and 76.0 times as high as that of the Au interdigital electrode integrated with the Ti 3 C 2 T x /WS 2 sensor (4.8%) and the MXene electrode integrated with the Ti 3 C 2 T x sensor (0.2%), respectively. Besides, this design performed at a limit of detection with 11.0 ppb NO 2 gas and displayed excellent stability under high humidities. Based on first-principles density functional theory calculation results, the improvement of the gas sensing performance can be mainly attributed to the heterojunction regulation effect, work function matching, and suppressing metal-induced gap states. This work provides a new approach for the design of flexible gas sensors on paper with MXene-based conductive electrodes and gas sensing materials.

Self-Powered Wearable Gas Sensors Based on l-Ascorbate-Treated MXene Nanosheets and SnO2 Nanofibers

“…Furthermore, the surface interaction of the NO 2 gas with the SM sensor is empirically recorded and the estimated value of β and correlation coefficient R are 0.49 and 0.98, respectively, as shown in Figure S8. As summarized in Table S1, − the sensing property of SM nanocomposite-based sensor in comparison with other sensors exhibit high sensing performance at ppb level concentration of NO 2 at RT.…”

Highly Selective and ppb-Level Butanone Sensors Based on SnO2/NiO Heterojunction-Modified ZnO Nanosheets with Electron Polarity Transport Properties

“…The close molarity of SnO 2 and NiO in the SnO 2 /NiO particles contributes to the abundant heterojunctions. The enriched heterojunction interface increases the charge transport barrier, inhibiting conductivity and carrier migration, which hinders the enhancement of SnO 2 /NiO sensing performance. Similarly, SnO 2 /NiO quantum dot modification on ZnO forms heterojunctions while increasing the active sites .…”

2D Materials in Flexible Electronics: Recent Advances and Future Prospectives

“…This bottleneck can cause low sensitivity, slow response time, and poor selectivity, which ultimately hinders the practical applications of gas sensors. Quan et al tried to address this issue by fabricating a gas sensor using a Ti 3 C 2 T x /WS 2 heterostructure as a gas sensing film and a Ti 3 C 2 T x -MXene nonmetallic electrode on a flexible paper via an ink-based approach . The developed Ti 3 C 2 T x /WS 2 was an innovative structure which exhibited a remarkable gas sensing performance toward NO 2 , with a sensor response of 15.2% for 1 ppm of NO 2 at room temperature (Figure d).…”