UV picosecond laser processing of fluorine-doped graphene for flexible in-plane micro-supercapacitors

With the characteristics of high precision, low damage, rapid heating and quick cooling, UV picosecond laser processing technique has shown broad application prospects in the fabrication of laser-induced graphene (LIG). In this study, fluorine-doped graphene films were processed by UV picosecond laser direct writing on fluorinated ethylene propylene (FEP) and polyimide (PI) composite films. The study focus on the effect of laser parameters on the sheet resistance, fluorine content of the LIG films and their applications in in-plane micro-supercapacitors. Results indicates that fluorine atoms can be successfully doped on the graphene surface by the optimization of laser power, scan pitch and defocus. The doped fluorine atoms not only enhance the conductivity and surface area of graphene but also exhibit hydrophobic properties rather than super-hydrophobicity due to the low surface energy of fluorine atoms, which is favorable for the interactions between electrolyte and electrodes. The fluorine-doped LIG-based micro-supercapacitors have an areal capacitance of ~4 mF/cm² . This research provides insights into the application of UV picosecond laser processing technique in the fabrication of functional materials, specifically focusing on the conductivity enhancement of fluorine-doped graphene for potential applications in flexible electronic devices.