Dual-mode Janus Structural-Color films toward an integrated sensing device with synergistic optical and electrical outputs

Abstract

Real-time sensing technologies have shown significant importance for environmental management, chemical monitoring, and industrial production. Current chemical sensors with high sensing performances toward gases or liquids have been realized individually; however, a simultaneous detection of targets in the both forms along with a low detection limit and a wide detection range remains a big challenge. Here, we present a novel switchable dual-mode Janus-structured sensor with integrated structural colors and electrical conductivity for chemical detection. The photonic layer formed by the self-assembly of cellulose photonic crystals shows highly selective responses to high-concentration targets via the color-changing channel, while the electrically conductive layer generated by the formation of carbon nanotube networks demonstrates target perceptions at low concentration and even ppm levels. Notably, the integrated sensor is further designed as a wearable sensing system for chemical monitoring in different application scenarios. These findings offer new thinking to design switchable multi-mode sensors for environmental and industrial surveillance.