Versatile Water-Based Transfer of Large-Area Graphene Films onto Flexible Substrates

Next-generation electronic devices are expected to demonstrate greater utility, efficiency and durability. Meanwhile, plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and variety of poly(para-xylylene) polymers enable transformational advantages to device shape, flexibility, weight, transparency and recyclability. Exhibiting a combination of outstanding mechanical, electrical, optical, and chemical properties of graphene with the plastic substrates could propose ideal material for the future flexible electronics. Chemical vapor deposition (CVD) allows cost-effective fabrication of a high-quality large-area graphene films, however, the critical issue is clean and noninvasive transfer of the films onto a desired substrate. The water-based delamination of CVD grown graphene on Cu can be considered as a "green" transfer process utilizing only hot deionized water. We investigated a method requiring only two essential steps: coating of 6-inch monolayer CVD graphene with transparent and flexible polymer, and Cu delamination in hot water. Proposed method is inexpensive, reproducible, environmentally friendly, waste-free and suitable for large-scale, high quality graphene. The transfer process demonstrated films with enhanced charge carrier mobility, high uniformity, free of mechanical defects, and sheet resistance as low as similar to 50 Omega/sq with 96.5 % transparency at 550 nm wavelength.