Effect of Au Nanorods on Potential Barrier Modulation in Morphologically Controlled Au@Cu2O Core-Shell Nanoreactors for Gas Sensor Applications

In this work, Au@Cu2O core-shell nanoparticles (NPs) were synthesized by simple solution route and applied for CO sensing applications. Au@Cu2O core shell NPs were formed by the deposition of 30-60 nm Cu2O shell layer on Au nanorods (NRs) having 10-15 nm width and 40-60 nm length. The morphology of Au@Cu2O core shell NPs was tuned from brick to spherical shape by tuning the pH of the solution. In the absence of Au NRs, cubelike Cu2O NPs having similar to 200 nm diameters were formed. The sensor having Au@Cu2O core shell layer exhibited higher CO sensitivity compared to bare Cu2O NPs layer. Tuning of morphology of Au@Cu2O core-shell NPs E from brick to spherical shape significantly lowered the air resistance. Transition from p- to n-type response was observed for all devices below 150 degrees C. It was demonstrated that performance of sensor depends not only on the electronic sensitization of Au NRs but also on the morphology of the Au@Cu2O core-shell NPs.