Electroless Plating of Copper on Laser-Induced Graphene for Flexible Hybrid Electronic Applications

Flexible hybrid electronics (FHEs) combine flexible substrates with conventional electronic components, offering increased mechanical stability and reduced size and weight. Laser-Induced Graphene (LIG) presents a novel approach for patterning flexible devices, characterized by reduced weight, flexibility, and ease of synthesis. This study demonstrates a new process utilizing copper-plated LIG to create direct-write, on-demand flexible electronics. The method incorporates catalytically active Pd nanoparticles into the LIG structure, enabling selective copper-plating to form circuits. This simplifies the process by eliminating sensitization steps and avoiding challenges of homogeneous deposition found in electroplating. The impact of laser fluence on LIG structure and plating behavior is systematically studied, identifying an optimal fluence of 168 J cm-2 using a 7 W, 450 nm laser. Samples with this fluence achieve complete copper plating within 20 min, a sheet resistance of 149.9 m ohm square-1, good adhesion, and durability across 10 000 bend cycles. An operational amplifier is produced on a flexible polyimide substrate, demonstrating the feasibility of this process for creating low-cost FHEs. This research expands LIG applications and establishes the relationship between laser fluence and copper-plating behavior, opening new opportunities for integrating LIG into flexible electronics.