Laser Shockwave-Induced Transformation of SWCNTs into Multi-Layer Graphene

We present a novel, one-step, chemical-free method for the structural transformation of single-walled carbon nanotube (SWCNT) networks into multi-layer graphene networks, achieved via a laser shockwave-induced compaction process at remarkably low temperatures (<176 °C). This transformation leverages high-rate repetitive pressure waves of 2.27 GPa, generated by the laser shockwave, to compact and structurally alter the SWCNT networks. The unique feature of this method is the controlled unzipping of defective SWCNT bundles, triggered by the intense shockwave compaction, which facilitates their evolution into double-layer graphene (DLG), few-layer graphene (FLG), and multi-layer graphene (MLG). Detailed structural analyses, including scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and Raman spectroscopy, confirm the emergence of graphene’s distinctive sixfold symmetry patterns at Miller-Bravais indices (hkil) {2110} and {1100}. This significant transformation results in up to a fivefold reduction in sheet resistance, showcasing the enhanced electrical properties of the resulting graphene networks. To the best of our knowledge, this highly effective, scalable synthesis approach for transforming SWCNTs into graphene networks is unprecedented. It opens new avenues for advanced applications in electronics, thermal management, and energy storage by finely tuning the junctions between SWCNT and graphene networks.