Improved gas sensing activity in structurally defected bilayer graphene.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Graphene, a 2D material, possesses inherent gas sensing properties.
• Optimizing graphene for enhanced gas detection remains an active research area.
• Structural modifications can influence graphene's electronic and sensing characteristics.

Purpose of the Study:

• To investigate the impact of controlled lattice disorder on graphene's gas sensing performance.
• To explore the use of focused ion beam (FIB) for introducing defects in graphene.
• To understand the sensing mechanism of defect-engineered graphene for nitrogen dioxide (NO2).

Main Methods:

• Controlled introduction of lattice disorder in graphene using focused ion beam (FIB) Ga(+) ion irradiation.
• Fabrication of gas sensors utilizing pristine and defect-engineered graphene.
• Electrical characterization of gas sensors in ambient conditions.
• Ab initio density functional theory (DFT) calculations to model gas molecule interactions with defects.

Main Results:

• Ga(+) ion irradiation successfully introduced controlled disorder (Stone-Wales defects) into the graphene lattice.
• Defected graphene exhibited a threefold increase in electrical response to NO2 gas compared to pristine graphene.
• DFT calculations revealed strong NO2 binding to Stone-Wales defects, altering electronic states near the Fermi level.
• The defect-engineered graphene sensor demonstrated faster response times and higher conductivity changes.

Conclusions:

• Gentle lattice disorder significantly enhances graphene's gas sensing capabilities for NO2.
• Stone-Wales defects are key sites for NO2 adsorption and signal transduction.
• Structurally defected graphene offers a promising platform for developing highly sensitive and responsive gas sensors.