▎ 摘　　要

We have explored an optimized electrochemical delamination technique to transfer large area graphene grown by chemical vapor deposition (CVD) technique. A selective soluble polystyrene (PS) layer was added above the polymethyl-methacrylate (PMMA)/graphene/Cu stack. With the help of this PS film, the stack could provide enough strength to be picked up directly from electrolyte and rinsed in several deionized (DI) water baths to eliminate H-2 bubbles and residual electrolysis ions. Besides, the PS layer was selective dissolved before the stack was transferred onto the target substrate leaving only the thin PMMA protective layer and graphene film scooped out onto the target substrate, which make sure that the thin and plastic film could fully stretch out on the substrate. As a result, the transferred graphene displayed high quality with less wrinkles, holes, and contaminants. This two-layer film-assisted electrochemical delamination technique is expected to play an important role in the application of two-dimensional materials in electrics, optoelectronics, and sensors.