Carbon Monoxide (CO) Sensor Based on Au Nanoparticles Embedded in a CuO Matrix by HR-LSPR Spectroscopy at Room Temperature

Optical gas sensors have emerged as an alternative to conventional conductometric sensors, opening new possibilities, especially for the detection of polluting and/or toxic molecules, such as carbon monoxide (CO). In this letter, an optimized plasmonic thin film, composed of Au nanoparticles embedded in a CuO matrix, was tested as a CO sensor, using high-resolution localized surface plasmon resonance (LSPR) spectroscopy. The Au:CuO thin film system was found to be highly sensitive, exhibiting a fast (~14 s) and reversible (~50 s) response when exposed to 50 ppm of CO, working at room temperature. Furthermore, the Au:CuO thin film prototype sensor presented a signal-to-noise ratio of 11, calculated at the transmittance minimum of the LSPR band, which allowed estimation of a detection limit as low as 14 ppm for CO gas.