Femtosecond Laser-Induced Graphene on 3D Printed Polymer With Enhanced Conductivity Via Laser Annealing

Abstract A femtosecond laser with an infrared wavelength (1030 nm) and a pulse duration of 200 femtoseconds (fs) was utilized to directly induce graphene tracks on rough 3D-printed polyetherimide (ULTEM-9085) substrates. The inherent surface roughness of the 3D-printed sample and the print defects leads to significant challenges in achieving uniform and continuous graphene formation, which could be overcome through the regulation of the laser focus. By precisely overlapping multiple laser-induced graphene (LIG) tracks, a continuous LIG area was successfully produced, demonstrating the feasibility of large-area graphene patterning on rough polymeric substrates. Moreover, a secondary laser scan at lower laser fluence was applied to the preformed LIG, leading to an enhancement in the electrical conductivity. This improvement is attributed to further structural re-organization, defect reduction, and potential removal of insulating polymer residues. The proposed approach provides an efficient and scalable strategy for fabricating conductive graphene patterns on complex polymeric surfaces, with potential applications in flexible electronics, sensors, and energy storage devices.