Visible Light-Driven p-Type Semiconductor Gas Sensors Based on CaFe₂O₄ Nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Metal oxides (MOx) are widely used in gas sensing.
• Visible light-activated sensors offer potential for low-power operation.
• Calcium iron oxide (CaFe2O4) is a p-type semiconductor with a bandgap suitable for visible light activation.

Purpose of the Study:

• To develop and characterize conductometric gas sensors based on p-type CaFe2O4 nanoparticles.
• To investigate the performance of these sensors for ethanol detection under visible light illumination.
• To evaluate the role of light wavelength and intensity on sensor response and recovery.

Main Methods:

• Synthesis of p-type CaFe2O4 nanoparticles.
• Fabrication of conductometric gas sensors.
• Testing sensor response to ethanol (reducing gas) under different LED wavelengths (465-640 nm).
• Comparison of light-activated versus dark conditions.

Main Results:

• CaFe2O4 sensors detected ethanol down to 100 ppm reversibly using LED illumination.
• The highest response was achieved with blue LED (465 nm) activation.
• Visible light illumination significantly improved sensor recovery time compared to dark conditions.
• Sensors showed functionality solely powered by LED energy, indicating potential for low-power applications.

Conclusions:

• p-type CaFe2O4 nanoparticles are promising materials for visible light-activated conductometric gas sensors.
• LED illumination, particularly blue light, enhances ethanol detection and recovery.
• These sensors offer a viable low-power alternative for detecting reducing gases like ethanol.