Highly sensitive and selective CO gas sensor based on a hydrophobic SnO2/CuO bilayer

Here, we have deposited bare SnO2 and SnO2/CuO bilayer thin films directly on porous anodic alumina (AAO) by pulsed laser deposition and then used them as a gas sensor without additional processing. The bilayer sensor shows remarkably high and selective responses to CO gas compared with bare SnO2 in a low detection range 5-500 ppm. Sensor response, selectivity, and stability studies reveal excellent sensing of the thin films. The working principle and role of hydrophobicity behind their good performance was discussed.