Advanced manufacturing of high conductive graphene coatings on polyethylene terephthalate substrate through laser-induced processes and thermal optimization

Abstract

Graphene holds immense promise for applications in sensors due to its exceptional properties such as large carrier mobility and high electrical and thermal conductivities. Nevertheless, the manufacture of high conductive graphene films onto flexible substrates remains a formidable challenge. This paper presented a novel method for the precise incorporation of high conductive graphene coatings onto polyethylene terephthalate (PET) through the back transfer of laser-reduced graphene oxide (LRGO) from Al2O3 ceramic to PET. A record-low sheet resistance for LRGO so far, approximately 12 Ω/sq. was achieved, meantime exhibiting 5B level adhesion performance with PET substrate. The sheet resistance of the transferred LRGO was measured and demonstrated to be adjustable by manipulating laser power, scanning speed, and hatch distance. The analysis of reduction of graphene oxide (GO) involved a comprehensive examination of alterations in topography image, chemical bond content, C/O atomic ratio, and ID/IG intensity ratio. These observations provided insights into the factors contributing to the decrease of sheet resistance within LRGO. The adoption of a continuous gigahertz (GHz) femtosecond laser as the light source, coupled with the incorporation of thermally conductive Al2O3 plate as a heat sink, facilitated the manufacturing processes including reduction and transfer of GO. The manufacture of graphene coatings with high electrical conductivity on PET in a versatile and cost-effective manner, presents significant potential for diverse applications, particularly in conductive-coatings-based sensors.