A room-temperature operable and stretchable NO2 gas sensor composed of reduced graphene oxide anchored with MOF-derived ZnFe2O4 hollow octahedron

Stretchable and highly sensitive gas sensors are currently receiving great attention due to their pertinence in wearable technology for detecting environmental conditions as well as for human safety. Herein, room temperature operable, stretchable, highly selective, and stable gas sensors were engineered by decorating networked reduced graphene oxide (rGO) with metal-organic framework-derived zinc ferrite (ZnFe2O4) microparticles on a three-dimensionally micropatterned stretchable polydimethylsiloxane substrate which is mountable on human skin for possible e-skin applications. The effect of mesoporous ZnFe2O4 microparticles concentration on gas sensing performance was investigated. Due to the existence of high-density defect sites in the mesoporous microparticles, the introduction of ZnFe2O4 in the rGO-based chemiresistive sensor demonstrated fast detection performance for nitrogen dioxide (NO2) across a wide range from 50 to 4,000 ppb with improved sensitivity (219.44 % ppm(-1)) and lower limit of detection (1.49 x 10(-4) ppm) compared to the pristine rGO-based sensor. The rGO-ZnFe2O4-based gas sensor showed good reproducibility and stable dynamic responses under application of static and dynamic stretching as well as workability in high humidity (up to 80 %) conditions even in the low concentration range (from 50 to 250 ppb) of NO2. These beneficial features of the stretchable gas sensors demonstrate their excellent potential for wearable gas sensing technology applications.