Room-temperature highly sensitive and selective NH₃gas sensor using vertically aligned WS₂nanosheets

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Development of efficient and selective gas sensors is crucial for environmental monitoring and industrial safety.
• Tungsten disulfide (WS2) is a promising 2D material for electronic applications, including sensing.
• Existing WS2-based sensors often face challenges with response time and selectivity.

Purpose of the Study:

• To fabricate and characterize a room-temperature ammonia (NH3) gas sensor using WS2 nanosheets.
• To evaluate the gas-sensing performance of WS2 nanosheets towards various analytes.
• To investigate the underlying mechanisms responsible for the observed sensing behavior.

Main Methods:

• WS2 nanosheets were synthesized using a facile and low-cost probe sonication method.
• Gas-sensing properties were tested for ammonia, ethanol, methanol, formaldehyde, acetone, chloroform, and benzene at 35 °C.
• Device performance metrics including sensitivity, response/recovery times, and limit of detection were analyzed.
• Raman spectroscopy was employed to study the interaction between NH3 and WS2.

Main Results:

• The fabricated WS2 nanosheet sensor demonstrated high selectivity towards NH3.
• The sensor exhibited excellent sensitivity (112% response) with a low limit of detection (5 ppm).
• Rapid response (54 s) and recovery (66 s) times were achieved, outperforming previously reported WS2 nanostructures.
• Raman spectroscopy indicated strong electron-phonon coupling between NH3 and WS2.

Conclusions:

• Room-temperature NH3 gas sensing using WS2 nanosheets is feasible and highly effective.
• The facile synthesis method yields WS2 nanosheets suitable for high-performance gas sensors.
• The enhanced performance is attributed to the unique properties of WS2 nanosheets and their interaction with NH3 molecules.
• The study highlights the potential of scaled 2D materials, especially with inter-digitized electrodes, for advanced sensing applications.