Highly sensitive and flexible NO₂ gas sensor based on nitro-functionalized graphene film

Area of Science:

• Materials Science
• Chemical Engineering
• Sensor Technology

Background:

• Graphene's unique electronic properties make it promising for gas sensing applications.
• Developing flexible and highly sensitive gas sensors for environmental monitoring is crucial.
• Nitrogen dioxide (NO2) is a harmful pollutant requiring effective detection methods.

Purpose of the Study:

• To develop a flexible gas sensor for nitrogen dioxide (NO2) detection.
• To enhance the sensing performance of graphene through chemical functionalization.
• To investigate the operational stability and mechanical flexibility of the sensor.

Main Methods:

• CVD-grown graphene films were functionalized with nitro groups using diazonium chemistry.
• Raman spectroscopy and X-ray photoelectron spectroscopy confirmed the chemical modification.
• Gas sensing performance was evaluated at 150 °C with varying NO2 concentrations.

Main Results:

• Nitro-functionalized graphene demonstrated an enhanced response to low-concentration NO2 compared to pristine graphene.
• The sensor exhibited stable operation during repeated gas exposure and mechanical bending.
• Improved sensitivity is attributed to the electron-withdrawing nature of nitro groups promoting p-type behavior.

Conclusions:

• Chemical functionalization of graphene is an effective strategy for improving NO2 sensor performance.
• Nitro-functionalized graphene shows potential for flexible and sensitive gas sensing platforms.
• The developed sensor offers stable and reliable detection of nitrogen dioxide.