Direct Laser Writing of Laser-Induced Graphene for flexible EMI shielding applications

Abstract

As electronic devices become an inseparable part of modern life, the challenge of electromagnetic interference (EMI) continues to grow, driving the demand for next generation shielding materials that are not only lightweight and flexible but also highly efficient in safeguarding future technology. Graphene, a carbon-based material, has attracted significant attention for EMI shielding applications due to its exceptional properties. Various methods exist for producing graphene, such as mechanical exfoliation, chemical vapor deposition, and the reduction of graphene oxide. However, among these, direct laser writing (DLW) has recently gained the most recognition. This method stands out due to its scalability, cost-effectiveness, patternability, and eco-friendliness, making it superior to other graphene production techniques. Additionally, the graphene produced using this approach has demonstrated excellent potential for use in EMI shielding. As a proof-of-concept, we explore the performance of laser-induced graphene (LIG) derived via different DLW techniques, in particular, CO2, fiber, and ultraviolet (UV) laser systems, for EMI shielding. The effects of laser parameters, particularly laser fluence, on graphene microstructure, electrical conductivity, and EMI shielding effectiveness are systematically investigated. Results indicate that CO2 and fiber lasers both produce highly conductive and structurally optimized LIG with a total shielding effectiveness of 28.6 dB and 29.8 dB, respectively, whereas UV laser processing results in lower conductivity and reduced shielding performance. To enhance EMI shielding, a novel LIG- polydimethylsiloxane (PDMS) hybrid shield (LPHS) is developed, integrating multilayer LIG within a PDMS matrix. The LPHS design significantly improves the shielding efficiency up to 40 dB through enhanced absorption and multiple reflection pathways while maintaining flexibility and handleability of the shields. This study provides a comprehensive framework for optimizing LIG synthesis for EMI shielding applications, paving the way for scalable and cost-effective solutions in modern electronic systems.