Xenes-based QCM sensors: exploring borophene and silicene for humidity sensing

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Borophene and silicene, members of the Xene family, possess high surface reactivity and stability.
• Their gas sensing capabilities, particularly in pristine forms, require systematic investigation.

Purpose of the Study:

• To investigate the relative humidity sensing capabilities of borophene and silicene.
• To model the adsorption-desorption mechanisms in these novel 2D materials for sensor applications.

Main Methods:

• Synthesis of borophene and silicene nanosheets via liquid-phase exfoliation.
• Characterization using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis.
• Fabrication and testing of quartz crystal microbalance (QCM) sensors for humidity detection.

Main Results:

• Borophene and silicene QCM sensors demonstrated stable and sensitive relative humidity detection.
• Sensitivities of 3.2 Hz/%RH (borophene) and 3.9 Hz/%RH (silicene) were achieved.
• Response/recovery times and hysteresis were quantified, with chemisorption identified as the dominant sensing mechanism.

Conclusions:

• 2D borophene and silicene exhibit significant potential for humidity sensing applications.
• The materials offer stable performance, suitable for environments requiring air stability.
• Chemisorption mechanism, supported by thermodynamic modeling, underpins their sensing capabilities.