Graphene functionalised by laser-ablated V₂O₅ for a highly sensitive NH₃ sensor.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Graphene is a promising material for gas sensors.
• Defects in graphene can significantly improve sensor response.
• Metal or metal oxide nanoparticles can introduce these defects.

Purpose of the Study:

• To functionalize single-layer graphene with vanadium pentoxide (V2O5) using pulsed laser deposition (PLD).
• To investigate the effect of V2O5 functionalization on graphene's gas sensing properties, specifically for ammonia detection.
• To analyze the structural changes induced in graphene by the PLD process.

Main Methods:

• Chemical Vapor Deposition (CVD) grown single-layer graphene was used.
• Pulsed Laser Deposition (PLD) was employed to deposit a thin V2O5 layer (≈0.6 nm) onto graphene.
• Raman spectroscopy was utilized to assess structural modifications in graphene.
• Chemiresistive sensing measurements were performed for ammonia detection at room temperature.

Main Results:

• Pulsed Laser Deposition (PLD) successfully functionalized graphene with V2O5, inducing defects.
• The V2O5-functionalized graphene chemiresistive sensor exhibited significantly improved ammonia sensing compared to unmodified graphene.
• Key sensing parameters including response time, sensitivity, and reversibility were substantially enhanced.

Conclusions:

• V2O5 functionalization via PLD is an effective method to improve graphene-based gas sensors.
• The enhanced performance is attributed to increased gas adsorption sites and nanophase boundaries formed between V2O5 and graphene.
• This approach offers a viable pathway for developing high-performance, room-temperature ammonia sensors.