Highly Sensitive NO₂ Gas Sensors by Spark Ablation on CVD Graphene

This work reports, for the first time, the use of spark ablation with impaction printing to selectively deposit silver (Ag) and gold (Au) nanoparticle (NP) functionalization on single-layer graphene (SLG) based gas sensors. This method avoids lithography and chemical processes, maintaining the device's quality while potentially lowering the fabrication costs. Ag-decorated sensors reveal a three-fold improvement in nitrogen dioxide (NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>) gas response over pristine-SLG sensors. We demonstrate detection capabilities down to 50 ppb at room temperature, negating the requirement for external thermal or photoactivation. In contrast to pristine or Au-decorated SLG sensors, Ag-decorated devices exhibit 96% recovery at room temperature (RT). These results highlight the potential of using spark ablation with impaction printing for functionalizing graphene-based sensors.