A novel room-temperature nitrogen dioxide gas sensor based on silver-doped cerium oxide thin film

In this study, thin films of cerium oxide (CeO2) and cerium oxide doped with silver nanoparticles (Ag NPs) were fabricated using the thermal vacuum evaporation technique. The structural analysis identified cubic Cerianite Polycrystalline structures and the crystallite size decreased from 8.6 nm to 6.8 nm when Ag NPs were doped into the CeO2. The undoped CeO2 film exhibited significant absorption at 400 nm, whereas doping with Ag NPs resulted in a slight blue shift toward shorter wavelengths, raising the energy bandgap to 2.9 eV. The Ag NPs content in CeO2 film demonstrated improved NO2 sensing performance. At 25 degrees C, the doped sample responded to 5 ppm NO2 with a value of 134 %, which was 1.4 times greater than that of undoped CeO2. The gas-sensing mechanism, repeatability, selectivity, and stability of the developed sensors were investigated and discussed.