Au@Cu2O core–shell nanoparticles as chemiresistors for gas sensor applications: effect of potential barrier modulation on the sensing performance

Abstract

Au@Cu₂O core–shell nanoparticles (NPs) were synthesized by a solution method at room temperature and applied for gas sensor applications. Transmission electron microscopy (TEM) images showed the formation of Au@Cu₂O core–shell NPs, where 12–15 nm Au NPs were covered with 60–30 nm Cu₂O shell layers. The surface plasmon resonance (SPR) peak of Au NPs was red-shifted (520–598 nm) after Cu₂O shell formation. The response of Au@Cu₂O core–shell NPs was higher than that of bare Cu₂O NPs to CO at different temperatures and concentrations. Similarly, the response of Au@Cu₂O core–shell NPs was higher than that of bare Cu₂O NPs for NO₂ gas at low temperature. The improved performance of Au@Cu₂O core–shell NPs was attributed to the pronounced electronic sensitization, high thermal stability and low screening effect of Au NPs.