Rapid, One-Step Synthesis of Laser-Scribed Graphene Sensor for Self-Activated Chemiresistive NO₂ Detection

Recently, laser-scribed graphene (LSG) has gained significant attention in sensor applications due to its cost-effectiveness, simplicity, environmental friendliness, excellent conductivity, and high thermal stability. Compared with many other graphene fabrication methods, LSG stands out as a promising approach for developing advanced sensors. In this study, we present a rapid, one-step synthesis for fabricating a highly sensitive and selective LSG sensor for self-activated chemiresistive detection of nitrogen dioxide (NO₂). Sensors were characterized using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoemission spectroscopy, Hall measurement, and a thermographic infrared (IR) camera. The LSG-based chemiresisitve sensor exhibited high electrical conductivity with a sheet resistance of around 23.4 ± 0.8 Ω/sq at room temperature and highly sensitive, selective, and fully reversible responses to NO₂ without external heating. Three-dimensional porous graphene plays an essential role in long-term reliability (42 days) in its self-activated state. Also, the sensor demonstrated a detection limit of parts per billion (ppb) levels of 2.68 ppb with high reliability. This rapid, one-step synthesis method provides a promising approach for the scalable production of high-performance graphene-based sensors for gas detection.