Restoring adsorption properties of graphene sensor with printable glass encapsulation using UV illumination

Graphene is a 2D material that has been widely researched for its potential as a gas-sensing material, but its environment-sensitive electronic properties have limited its use in practical applications. In this work, a graphene chemi-resistive sensor is first integrated with a 3D-printed fused silica chamber with an internal volume of 50 microliters. The adsorption properties of graphene film are then regenerated using ultraviolet illumination. We have shown in this work that sensor response towards the target acetone sample can be regained successfully after more than 2 months of operation using UV illumination. The sensor's response at room temperature towards direct on-chip injection of acetone vapor ranging from 5 ppm to 1,000 ppm was studied and the data was linearly fitted. The wide dynamic response of the graphene sensor was used to demonstrate its usability for practical soil testing applications. We successfully detected 11 ppm, 20 ppm and ∼605ppm of acetone vapor in artificially spiked soil samples. In conclusion, our new on-chip integrated gas chamber is extremely robust, provides repeatable results after long-term operation, and offers a direct route for on-chip sample injection.