Detection of H2 facilitated by ionic liquid gating of tungsten oxide films

Abstract

Molecular hydrogen (H2) shows promise as a future renewable energy carrier. However, due to safety concerns, its reliable detection in different atmospheres is an important issue. Here, we propose a hydrogen sensor based on ion-gated transistors exploiting the interface between tungsten oxide and ionic liquids. Two different approaches to gas sensors (metal oxide gas sensor and ionic liquid-based electrochemical sensor) are integrated in a single device. We demonstrate that ionic liquid gating enhances the effect of H2 on the tungsten oxide transistor channel. The transistor current response permits the detection of H2 in an O2-free environment with the device operating in room temperature. After H2 sensing, the initial properties of the tungsten oxide channel can be recovered by exposure to O2.