Laser Irradiation and Property Correlation in Double-Lasing Processes on Laser-Induced Graphene Electrodes.

The fabrication of laser-induced graphene (LIG) electrodes by direct laser writing techniques has received considerable attention due to its simplicity, versatility, and cost-effectiveness for electrochemical applications in both sensing and energy storage. In general, a single-lasing irradiation process is used to prepare LIG electrodes. However, the intrinsic features of LIG can be further improved by taking advantage of additional lasing processes, even without any chemical treatments. In this work, we investigated the potential enhancement of LIG's electrochemical performance through a double-lasing irradiation process. This process does not require any chemical modification of the LIG to improve its electrochemical performance. Importantly, we revealed the correlation between laser irradiation and the properties of LIG electrodes prepared through the lasing process. We evaluated the characteristics of LIG electrodes prepared by the single-lasing and double-lasing irradiation regarding their microstructures and electrochemical features, including the sheet resistance (R), specific areal capacitance (C), peak-to-peak separation (Δ), and peak current. The double-lasing LIG exhibited improved electrochemical properties, especially low R and Δ values. This improvement results from a higher degree of graphitization, making them advantageous for developing electrochemical sensors. This was demonstrated by the improved electrochemical sensing of HO using the double-lasing LIG.