Fig. 2: Comparative analysis of the stretchability of the Au and graphene-Au nanomembranes.

a, b Schematic of the fracture behavior (top panel) and corresponding SEM images (bottom panel) of the Au and graphene-Au nanomembranes, respectively. c Normalized currents versus strain of the graphene-Au (red line) and Au (blue line) nanomembranes with the insets showing photographs of the graphene-Au resistor being stretched by a numerical control motorized positioning platform. d, e SEM images showing the morphology of the Au and graphene-Au nanomembranes under varying degrees of strains, respectively. f Statistical results of the length of cracks versus strain of the graphene-Au (red line) and Au (blue line) nanomembranes. g Statistical results of the density of cracks versus strain of the graphene-Au (red line) and Au (blue line) nanomembranes. h Optical images of LEDs powered by 3 V connected to the graphene-Au electrodes under different strains. The LEDs kept luminous when the strain is extended to 12%. i Optical images of LEDs powered by 3 V connected to the Au electrodes under different strains for comparison, showing that the LEDs extinguished when the strain exceeds 5%. j Optical image of the “SIMIT” logo consisting of 48 LEDs under stretching.