CO2, Fiber, and UV Direct Laser Writing of Graphene for Flexible EMI Shielding Applications: A Comparative Study

As electronic devices become an inseparable part of modern life, the challenge of electromagnetic interference (EMI) continues to grow. This drives the demand for next generation shielding materials that are not only lightweight and flexible but also highly efficient in safeguarding communication, computing, and other advanced electronic technologies. Although graphene is regarded as an excellent candidate for EMI shielding applications, challenges associated with its traditional synthesis routes (chemical or electrochemical), together with its inherently hydrophobic nature, hinder its patterning and thereby limit widespread adoption. This study explores the direct laser writing of laser-induced graphene (LIG) as a facile approach to create patterned EMI shields in few second. It compares the efficiency of CO₂, fiber, and ultraviolet (UV) laser systems on LIG synthesis and assesses the compatibility of each laser source in terms of EMI shielding performance. The effects of laser parameters, particularly laser fluence, on graphene microstructure, electrical conductivity, and EMI shielding effectiveness are systematically investigated. Results indicate that fiber and CO₂ lasers produce highly conductive and structurally optimized LIG with a total shielding effectiveness of , whereas UV laser processing results in lower conductivity and reduced shielding performance. Additionally, the effects of overlapping LIG lines and structural patterns on EMI shielding properties are investigated. In the final phase of this work, a flexible and robust LIG—polydimethylsiloxane (LIG-PDMS) hybrid shield (LPHS) is developed, integrating bilayer LIG within a PDMS matrix. The LPHS design significantly improves the shielding efficiency up to 42 dB through enhanced absorption and multiple reflection pathways. 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.