Optical Hydrogen Sensing Properties of e-Beam WO₃ Films Decorated with Gold Nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Tungsten oxide (WO3) is a promising material for gas sensing applications.
• Optical sensing offers advantages like high sensitivity and selectivity.
• Nanoparticle coatings can enhance material performance.

Purpose of the Study:

• To synthesize and characterize tungsten oxide thin films for optical hydrogen sensing.
• To investigate the effect of film properties (thickness, crystallinity, morphology) on sensing performance.
• To evaluate the selectivity of the developed sensors towards hydrogen gas.

Main Methods:

• E-beam deposition and post-synthesis treatments (thermal, acid boiling) for WO3 film fabrication.
• Gold nanoparticle coating for enhanced optical properties.
• Characterization using X-ray diffraction, scanning electron microscopy, ellipsometry, and UV-VIS spectroscopy.
• Optical sensing measurements in air with exposure to hydrogen, ammonia, and carbon monoxide.

Main Results:

• Synthesized WO3 films with varying thicknesses, crystallinity, and morphologies.
• Demonstrated effective optical sensing of hydrogen gas in air.
• Achieved good selectivity against common reducing gases like ammonia and carbon monoxide.
• Identified a strong dependence of sensor sensitivity on film thickness and crystallinity.

Conclusions:

• Tungsten oxide thin films coated with gold nanoparticles are effective optical sensors for hydrogen.
• Film thickness and crystallinity are critical parameters for optimizing hydrogen sensing sensitivity and selectivity.
• The developed sensor shows potential for selective hydrogen detection in complex gas mixtures.