Multifunctional graphene woven fabrics

Abstract

Tailoring and assembling graphene into functional macrostructures with well-defined configuration are key for many promising applications. We report on a graphene-based woven fabric (GWF) prepared by interlacing two sets of graphene micron-ribbons where the ribbons pass each other essentially at right angles. By using a woven copper mesh as the template, the GWF grown from chemical vapour deposition retains the network configuration of the copper mesh. Embedded into polymer matrices, it has significant flexibility and strength gains compared with CVD grown graphene films. The GWFs display both good dimensional stability in both the warp and the weft directions and the combination of film transparency and conductivity could be optimized by tuning the ribbon packing density. The GWF creates a platform to integrate a large variety of applications, e.g., composites, strain sensors and solar cells, by taking advantages of the special structure and properties of graphene.

Figure 1. Fabrication of GWFs by CVD using copper wire meshes as substrates.

(a) Schematic of steps for GWF preparation. (b) Macroscopic optical images (left), top-view SEM images (right) of copper meshes before (top) and after (bottom) graphene growth. Scale bars, 200 μm. (c) Optical images of GWF films floating on water and deposited on glass and PET. Scale bars, 5 mm. (d) TEM image of a GMR and selected area electron diffraction pattern from the region marked with a yellow box. Scale bars, 50 nm (left), 5 (1/nm) (right).

Figure 2. Large-area, CVD grown GWFs in supported and free-standing states.

(a) Large-area optical image of a representative region of a GWF film. Scale bar, 100 μm. Inset shows the optical image of a nylon woven fabric for comparison. Scale bar, 200 μm. (b) Top-view optical image (Scale bar, 50 μm) and (c) High magnification SEM images of cross-sectional views of the interlacing points of GMRs. Scale bars, 5 μm (top), 1 μm (bottom). (d) Optical images of flexible GWF/PDMS composite films. Scale bar, 5 mm. The top inset shows the twisted GWF film by tweezers. The bottom inset shows the cross-section view SEM image of the composite film. Scale bar, 100 μm.

Figure 3. Macroscale GWFs with tunable GMR packing density.

(a) Macroscopic optical images of three different GWFs (Scale bars, 300 μm) and (b) corresponding representative small-area SEM views of these three samples. Scale bars, 200 μm. (c) Ultraviolet–visible-near infrared transmission spectra and (d) transparency (at 550 nm) versus sheet resistance plots.

Figure 4. GWF/polymer hybrid films.

(a) Resistance-strain curves for GWF/PDMS hybrids along different directions. Inset shows the schematics and corresponding optical images. Scale bars, 300 μm. (b) Electromechanical properties of the GWF/PDMS films. Resistance change relative to the original value (ΔR/R₀) recorded for a number of cycles at tensile strains of 2% and 5%. (c) Stretchable sensor fixed to a finger, and relative changes in resistance for finger motion. Insets show corresponding photographs.

Figure 5. GWF-based solar cells.

Device schematics, energy band structure diagrams and J-V curves of (a) GWF/Si solar cell, (b) PEDOT filled GWF/Si solar cell and (c), hybrid Schottky and PEC GWF/Si solar cell.