Laser-induced graphene (LIG) uses a CO2 infrared laser scriber for transforming specific polymer substrates into porous graphene. This technique is simple, scalable, low-cost, free of chemicals, and produces a 3D graphene for applications across many fields. However, the resulting 3D graphene is highly sensitive to the lasing parameters used in their production. Here, we report the effects of power, raster speed, number of lasing passes (with and without spot overlapping) on the resulting LIG structure, morphology, and sheet resistance, using a polyimide (PI) substrate. We find that the number of lasing passes, laser spot overlapping and brand of PI used had a strong influence on the quality of the LIG, measured in terms of the IG/ ID and I2D Raman bands and sheet resistance. Increasing number of passes and overlapping of laser spots led to increased LIG pore sizes, larger graphene scales, and reduced sheet resistance. Furthermore, the over-the-counter desktop CO2 laser engraving unit used introduced additional restrictions that limited the quality of the LIG produced, particularly due to inconsistent control of the laser scribing speed and a poor thermal management of the laser unit.

    Abstract
    1 Introduction
    2 Materials and methods
    3 Results and discussion
        3.1 Effect of engraving parameters on LIG
        3.2 Influence of engraving parameters and PI brand on the LIG crystal structure
        3.3 Influence of engraving parameters and PI type on the surface morphology and sheet resistance of LIG samples
    4 Conclusions
    Acknowledgements 
    References

• Jhonattan de la Roche(OMICAS Alliance, Pontificia Universidad Javeriana)
• Isabella López‑Cifuentes(OMICAS Alliance, Pontificia Universidad Javeriana)
• Andres Jaramillo‑Botero(OMICAS Alliance, Pontificia Universidad Javeriana, Chemistry and Chemical Engineering Division, California Institute of Technology)