Substoichiometric two-dimensional molybdenum oxide flakes: a plasmonic gas sensing platform

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Two-dimensional (2D) molybdenum oxides show potential for plasmon resonance in visible light.
• Plasmonic nanomaterials are increasingly explored for sensitive detection applications.

Purpose of the Study:

• To demonstrate the use of plasmonic 2D molybdenum oxide flakes for gas sensing.
• To investigate the interaction of hydrogen gas with these 2D materials and its effect on plasmonic properties.

Main Methods:

• Fabrication of 2D molybdenum oxide flakes via grinding-assisted liquid exfoliation.
• Induction of substoichiometric quasi-metallic form through simulated sunlight exposure.
• Exposure to hydrogen gas and monitoring of changes in plasmonic properties.

Main Results:

• Quasi-metallic 2D molybdenum oxides transform into semiconducting states upon exposure to hydrogen (H2).
• This transformation leads to a gradual loss of plasmonic properties, enabling detection.
• The sensing platform demonstrated performance across various H2 concentrations and operating temperatures.

Conclusions:

• Plasmonic 2D molybdenum oxide flakes offer a novel platform for gas sensing.
• The reversible or irreversible changes in plasmonic properties upon gas interaction can be leveraged for sensing mechanisms.
• This approach presents opportunities for advanced optical and sensing technologies.