Low temperature inkjet-printed metal oxide sensors for sensitive and selective NO₂ detection

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Gas sensor technology is vital for environmental monitoring and pollution control.
• Inkjet printing offers a cost-effective and scalable method for fabricating gas sensors.
• Nitrogen dioxide (NO2) is a significant air pollutant from industrial and vehicular sources.

Purpose of the Study:

• To develop and characterize inkjet-printed chemiresistive gas microsensors using tin oxide (SnO2) and indium oxide (In2O3).
• To evaluate sensor performance for nitrogen dioxide (NO2) detection.
• To assess sensor integration potential on CMOS-compatible microchips.

Main Methods:

• Fabrication of microsensors on CMOS-compatible microchips with integrated microheaters and electrodes.
• Deposition of SnO2 and In2O3 sols via inkjet printing.
• Characterization of sensor response, sensitivity, selectivity, and stability to NO2.

Main Results:

• SnO2 sensor detected NO2 down to 10 ppb at room temperature.
• In2O3 sensor showed optimal performance at 100 °C with similar detection limits.
• Both sensors exhibited linear response, high selectivity against interfering gases, and robustness against humidity fluctuations.

Conclusions:

• Inkjet-printed metal oxide microsensors are a viable technology for sensitive and selective NO2 detection.
• The developed sensors are suitable for miniaturization and integration into portable sensing platforms.
• This technology advances the development of compact, low-power environmental monitoring systems.