SnO₂-Based NO₂ Gas Sensor with Outstanding Sensing Performance at Room Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Efficient gas sensors rely on controlled surface properties of metal oxide semiconductors.
• Oxygen vacancies are crucial for enhancing gas-sensing performance.

Purpose of the Study:

• To investigate the gas-sensing behavior of tin oxide (SnO2) nanoparticles for various gases.
• To explore the role of oxygen vacancies in SnO2 gas sensors.
• To optimize SnO2 film synthesis for cost-effective gas sensing applications.

Main Methods:

• Sol-gel synthesis for SnO2 powder and spin-coating for film deposition.
• Characterization using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and UV-visible spectroscopy.
• Gas sensitivity testing using a two-probe resistivity measurement device.

Main Results:

• SnO2 films exhibited notable gas-sensing behavior for nitrogen dioxide (NO2), ammonia (NH3), carbon monoxide (CO), and hydrogen sulfide (H2S).
• The sensor demonstrated outstanding low-concentration detection capacity for NO2 (down to 0.5 ppm).
• High sensitivity to NO2 was observed at 2 ppm with response and recovery times of 184s and 432s at room temperature.

Conclusions:

• Controlled formation of oxygen vacancies significantly improves the gas-sensing capability of SnO2.
• The cost-effective sol-gel and spin-coating methods are suitable for producing SnO2 gas sensors.
• SnO2 nanoparticles show great potential for detecting harmful gases like NO2.