UV-VIS laser parameter effects on the physicochemical properties of Laser-Induced Graphene

Laser-induced graphene (LIG) is a versatile and scalable technique for the low-cost production of graphene-like sensing devices. However, the performance of these devices is hypersensitive to the engraving parameters used during fabrication. In this work, we systematically varied laser engraving speed and power to explore their influence on the physical and electrochemical properties of LIG electrodes to achieve low resistance, high LIG porosity, and enhanced sensitivity for future sensing applications. We employed a UV-VIS diode laser mounted on a CNC (Computer Numerical Control) system constructed by our team to engrave on polyimide sheets. Our results demonstrated that low and high-power settings led to poor electrode performance due to increased resistivity and structural damage. Conversely, electrodes fabricated at power settings between 60 % (3W) and 80 % (4W) of the laser’s maximum capacity, combined with maximum operable speed, exhibited uniform morphology, high conductivity, and reversible electrochemical behavior. Under these conditions, the resulting LIG-based electrodes featured porous graphene on networks with directional asymmetry, with an ID/IG ratio of approximately 1.3, a sheet resistance of 20 Ω/sq, and a peak current of 272.1 uA, alongside an Ipa/Ipc ratio near 1 in cyclic voltammetry measurements, providing a foundation for the development of efficient LIG-based sensors.