Humidity and selective oxygen detection by Ag₂S nanoparticles gas sensor

We report selective oxygen detection by Ag₂S nanoparticles gas and humidity sensor at low temperatures with high sensitivity. The Ag₂S nanoparticles with preferentially oriented plane (−112) and texture coefficient ~ 1.49 were synthesized by co-precipitation technique. The bandgap and surface area of Ag₂S nanoparticles was 2.03 eV and 16.30 m²/g respectively. The response of Ag₂S nanoparticles to detect different concentrations of oxygen, LPG, methanol, ethanol and 1-butanol at different temperatures (24–160 °C) was investigated. The Ag₂S nanoparticles exhibited a linear relationship between response versus concentration at different temperatures for the tested gases. However, the Ag₂S nanoparticles exhibited high response, shortest response/recovery time, good stability and recyclability to oxygen as compared to other tested gases at 160 °C. At room temperature the response of the Ag₂S nanoparticles relative humidity (RH) sensor increased linearly with increase in RH. Ag₂S nanoparticles as RH sensors also exhibited high response, short response/recovery time, good stability and recyclability.