Monolayer Sc₂CF₂ as a Potential Selective and Sensitive NO₂ Sensor: Insight from First-Principles Calculations

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Two-dimensional (2D) materials offer high surface-area-to-volume ratios for gas sensing applications.
• Scandium-based carbides and nitrides (MXenes) are emerging as promising 2D materials.

Purpose of the Study:

• To investigate the potential of monolayer Scandium Carbon Fluoride (Sc2CF2) as a gas sensor for NO2 detection.
• To explore the effects of adsorption, biaxial strain, and substrates on Sc2CF2's sensing properties.

Main Methods:

• First-principles calculations (Density Functional Theory) to study electronic and optical properties.
• Molecular Dynamics (MD) simulations to assess adsorption stability.
• Analysis of adsorption energy and charge transfer under varying conditions.

Main Results:

• Significant charge transfer between Sc2CF2 and NO2 due to LUMO-VBM alignment.
• Stable NO2 adsorption on Sc2CF2 at room temperature.
• Biaxial strain enhances adsorption energy and charge transfer, improving NO2 detection sensitivity.
• Hexagonal Boron Nitride (h-BN) substrate has minimal impact on Sc2CF2's sensing behavior.

Conclusions:

• Monolayer Sc2CF2 is a promising candidate for selective and sensitive NO2 gas sensing.
• The findings provide theoretical guidance for developing other terminated MXenes for gas detection applications.