Fabrication and transfer of laser induced graphene (LIG) electrode for flexible substrate-based electrochemical sensor applicatins

This paper describes the fabrication process of laser induced graphene (LIG) and its transfer method on to a flexible and stretchable PDMS substrate. By irradiating CO₂ laser on a polyimide(PI) film surface, a localized high temperature is created, resulting in a three-dimensional porous graphene network structure with good conductivity. This LIG electrode is relatively easy to fabricate and since it is very weak the LIG electrode was transferred to a flexible PDMS substrate to increase the sturdiness as well as possible use in flexible applications. Sheet resistance, thickness, and electrochemical activity of the fabricated in-situ LIG electrodes have been examined and compared with the LIG electrodes after transferring to PDMS elastomer. The properties of the LIG electrodes were also examined depending on the CO₂ laser power. As the irradiated laser power increased, the LIG electrode resistance decreases and the LIG electrode thickness increased. At 4.8 W of laser power, the average sheet resistance and thickness of the fabricated LIG electrodes were approximately 31.7 Ω/ □ and 62.67 μm, respectively. Moreover, the electrochemical activity of the fabricated LIG electrode at 4.8 W of laser power showed a high oxidation current of 28.2 μA after transferring to PDMS.