An Ultralight Graphene Honeycomb Sandwich for Stretchable Light-Emitting Displays

Materials that can simultaneously achieve excellent electrical conductivity and stretchability are essential components for the next-generation stretchable electronics. Herein, a highly conductive and stretchable graphene honeycomb (GHC) sandwich consisting of a porous GHC/polydimethylsiloxane (PDMS) composite core and ultrahigh-density graphene foam/PDMS composite face sheets is rationally assembled. The GHCs prepared by a 3D printing technique possess a long-range ordered hexagonal porous structure with an ultralow density of 3.25 mg cm⁻³ and deliver an excellent electrical conductivity of 72 S m⁻¹. To the best of authors' knowledge, they are the lightest honeycomb structure reported in open literature. The highly porous GHC core endows the sandwich with an ultralow resistance change over large external strains of 60% with excellent structural durability. A stretchable light-emitting display is demonstrated using the sandwich as the electric circuit and light-emitting diodes as the pixels, which exhibits reliable lighting performance under different loading conditions.