UV-activated WS2/SnO2 2D/0D heterostructures for fast and reversible NO2 gas sensing at room temperature

2D Transition metal dichalcogenide (TMDs) has been recognized as a potential candidate for constructing wearable and safe room temperature gas sensor. Especially, the heterostructures of TMDs/ metal oxide semiconductors (MOS) have been proved to be potential candidates as NO2 sensors at room temperature. However, the response/recovery rate and reversibility of the sensors is still not satisfactory due to the inefficient charge transfer on TMDs/MOS hetero-interface. In this study, SnO2 quantum dots (QDs) were simply decorated on the surface of few or single layer WS2 nanosheets to form 2D/0D heterostructures via a facile room temperature aqueous solution process and self-assembly method. The 2D/0D WS2/SnO2 heterostructure-based optoelectronic gas sensor showed fast response/recovery rates and full reversibility to NO2 at room temperature with enhanced response. The remarkable improvement in NO2 sensing was because of the efficient interfacial charge separation rendered by 2D/0D heterostructures under ultraviolet illumination. Therefore, this study points out a potential strategy for the design of light-enhanced gas sensing materials.