Investigation of picosecond laser-induced graphene for dopamine sensing: Influence of laser wavelength on structural and electrochemical performance

This research focuses on a straightforward synthesis method for laser-induced graphene using green (532 nm) and UV (355 nm) picosecond laser irradiation of graphene oxide dispersion. Structural analysis revealed that the laser operating at 355 nm is more favorable to producing a product with a higher content of the restored sp2 network, a higher graphene in-plane crystallite size, a higher concentration of pyrrolic N, and higher values of the optical bandgap. Conversely, the 532 nm laser yielded a sample with higher concentrations of epoxy groups, sp3 defects, and amorphous carbon. Electrochemical analysis for dopamine determination showed potential for both samples as electrode materials. However, the analytical parameters of the sample treated with the 355 nm laser surpass those of the 532 nm laser. It was assumed that the enhanced electrochemical activity results from the presence of pyrrolic N and vacancies in the structure of the sample treated with the 355 nm laser.