Gold-decorated laser-induced graphene for wearable biosensing and joule heating applications

Laser-induced graphene from polyimide (PI) substrate has attracted much attention due to its controllable morphology and patternable structure. However, the property of polyimide-derived graphene (PDG) should be further improved to meet the requirement of next-generation flexible devices. In this article, Au-modified PDG has been fabricated via the CO2 laser scribing on the common PI substrate. The obtained PDG with a foam-like morphology can provide large accessible sites for the deposition of Au nanoparticles (ANPs) by thermal evaporation. The ANP-PDG devices have been utilized as electrochemical and surface-enhanced Raman scattering (SERS) sensors for the detection of dopamine (DA), Rhodamine 6G (R6G), and Adenine (Ad), respectively. The properties of the electrothermal heater based on the ANP-PDG films are also investigated. Due to the high conductivity and unique plasmonic effect of ANPs, the ANP-PDG displays higher electrocatalytic activity and stronger SERS signals than that of bare PDG film. The ANP-PDG also can reach higher steady-state temperatures (Ts) compared to the bare PDG heater. Furthermore, the ANP-PDG devices precisely defined on the PI substrate reveal great mechanical flexibility and the sheet resistance is very stable without obvious change, which can be applied for next-generation flexible electronics.