Search

Laser-induced graphene (LIG) provides a three-dimensional porous structure of graphene, which is suitable for application to energy storage devices and flexible electronics. Controlling the morphology and structure of LIG and understanding its underlying principle are important for enhancing the performance of LIG-based devices. Here, we investigated the effects of graphene interfacing with a precursor material on the LIG formation. A CO2 laser with different powers and scan rates was irradiated on a polyimide film covered with mono-, bi-, and trilayer graphene to fabricate in situ LIG contacts. As the number of graphene layers increases, the threshold energy required for the LIG formation decreases. In addition, the interfacing graphene causes spreading and smoothing of the LIG electrodes in the in-plane direction. A numerical study on the effect of the interfacing graphene on heat transfer was also conducted. The simulation results showed that the graphene layer enhances thermal diffusion to facilitate the LIG formation; this was also observed in the experimental results. Our study on the interfacial effects of a nanomaterial on the LIG formation provides design guidelines for considering heat transfer in LIG electronics fabricated with heterogeneous materials and structures. [ABSTRACT FROM AUTHOR]

Graphene with an atomically thin structure is considered to be a highly sensitive transducer capable of converting diverse external stimuli into measurable electrical signals. The generated signals, such as current and resistance, can be extracted through electrical contact to graphene. Conventional methods for contact formation are usually based on physical deposition of conductive materials on the target graphene. Here, we propose a method for in situ chemical synthesis of electrical contacts to graphene as an alternative approach that complements conventional physical methods. CO2 laser irradiation on a polyimide film with monolayer graphene on top can convert the polyimide surface to conductive electrodes of laser-induced graphene (LIG) that electrically connect to the existing graphene channel. Laser-scribing conditions, such as the power and scan rate, can modulate the contact resistance of the LIG–graphene junction. Various arbitrary shapes of in situ LIG contacts can be scribed to the direct writing ability of the laser. The proposed in situ LIG contact method can be extended to other carbon nanomaterials, such as carbon nanotubes and PEDOT:PSS. As a proof of concept of the in situ LIG contacts to graphene for electronic device applications, graphene field-effect transistors were demonstrated on a graphene-supported polyimide substrate with LIG–graphene junctions as source/drain electrodes. Our approach will pave the way for the simple and low-cost fabrication of versatile graphene electronic devices by utilizing the existing LIG technology specialized for energy devices and sensors. [ABSTRACT FROM AUTHOR]

Numerous studies have focused on graphene owing to its potential as a next-generation electronic material, considering its high conductivity, transparency, superior mechanical stiffness, and flexibility. However, cost-effective mass production of graphene-based electronics based on existing fabrication methods, such as graphene transfer and metal formation, remains a challenge. This study proposes a simple and efficient method for creating electrical contacts with graphene. The method involves patterning a Cu foil after graphene growth, enabling the low-cost scalable production of graphene-based flexible electronics. The fabricated graphene devices exhibited linear current-voltage characteristics, indicating good electrical contact between the postgrowth-patterned Cu electrodes and graphene. The proposed postgrowth patterning method allows for the fabrication of Cu-contacted graphene devices on large areas and various flexible substrates, including ultrathin and stretchable films (<10 μm). The feasibility of the proposed method for electronic devices was demonstrated by implementing gas and flexible force sensors. The proposed approach advances the field of graphene-based electronics and holds potential for practical applications in various electronic devices, paving the way for scalable, cost-effective, and flexible technology solutions., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)