Self-heating effects on the toluene sensing of Pt-functionalized SnO₂-ZnO core-shell nanowires

Abstract

Embedding chemical sensors into mobile devices is an emerging demand in modern information converged technology. The unbearable power consumption to raise the temperature of chemoresitive-type chemical sensors makes it impossible for them to be embedded regardless of their peculiar sensing properties such as low cost, miniaturization, high response, and excellent stability and robustness. In this study, self-heated nanowire sensors were prepared by exploiting the synergic effect of the core–shell structure and catalytic nanoparticles. As a prototype approach, Pt nanoparticle-functionalized SnO₂–ZnO core–shell nanowires were synthesized, demonstrating extremely striking performance and characteristics. Thicker ZnO shell showed the larger self-heating and higher sensor response. The sensors exhibited excellent selectivity for toluene gas, with negligible responses to other reducing gases. This one possessed a considerable sensing performance at room temperature, even without a significant self-heating. The self-heated sensing of the novel core–shell nanowires developed required only an extremely low power consumption of 31 μW, suggesting their potential in applications as sensors embedded into mobile devices.