This work introduces Graphene Electronic Tattoos (GETs) 2.0, improved wearable tattoo sensors with superior electrical properties, breathability, and robustness compared to previous monolayer GETs. Multilayer GETs (2L and 3L) and the addition of graphene nanosheets (GNS) significantly enhance electronic properties, reducing sheet resistance by 3.5-fold and skin impedance by 2.5-fold, while also decreasing performance variability. The incorporation of microholes enables sweat permeability without compromising electrical performance and facilitates improved biplanar contact. Furthermore, multilayer GETs 2.0 function effectively as wearable electronic heaters, demonstrating heating efficiency of ~6 mW/°C.
