Tunable Volatile-Organic-Compound Sensor by Using Au Nanoparticle Incorporation on MoS₂

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Controlling charge concentration in two-dimensional (2D) materials is crucial for high-performance electronics and sensors.
• Functionalization methods are needed to dope 2D material channels for sensitive and selective chemical sensing.
• Molybdenum disulfide (MoS2) based sensors often exhibit limited selectivity to various volatile organic compounds (VOCs).

Purpose of the Study:

• To enhance the gas-sensing performance of MoS2 through controlled gold nanoparticle (Au NP) functionalization.
• To investigate the n-doping effect of Au NPs on MoS2 and its impact on chemical sensing.
• To enable tunable sensing of different VOCs using functionalized MoS2 for improved selectivity.

Main Methods:

• MoS2 was prepared using a chemical exfoliation process.
• Au nanoparticles (tens of nanometers) were decorated onto MoS2 by exploiting differences in reduction potential and work functions.
• Gas-sensing performance was evaluated for various VOCs and oxygen-functionalized compounds.

Main Results:

• Controlled Au NP functionalization significantly enhanced the gas-sensing performance of MoS2.
• Au NPs induced an n-doping effect in MoS2, facilitating electron charge transfer from Au to MoS2.
• The n-doping enabled tunable sensing of hydrocarbon-based VOCs and oxygen-functionalized compounds, overcoming the single-response limitation of pristine MoS2 sensors.

Conclusions:

• Controlled chemical doping using Au NPs is an effective strategy to tune the VOC-sensing performance of MoS2.
• This approach significantly improves the selectivity and sensitivity of MoS2-based gas sensors.
• The controllable doping process paves the way for developing multichannel sensing systems for early detection and pattern recognition of target analytes.