Direct growth of a porous substrate on high-quality graphene via in situ phase inversion of a polymeric solution†
The key for graphene applications is the successful transfer of graphene from a growth metal substrate to a substrate for application without compromising its high quality. However, state-of-the-art polymethyl methacrylate (PMMA) assisted transfer methods introduce wrinkles, folds and cracks, which are exacerbated for porous substrates. Here we report a novel in situ technique to transfer graphene onto a porous substrate which resolves these issues. Using phase-inversion a porous substrate is grown onto a graphene film with strong adhesion that perfectly matches graphene's topography, and the growth metal substrate is subsequently etched away. We achieve 63 cm2 high-quality single-layered graphene with almost 100% coverage over the pores of the substrate and pore ratios up to 35%. Our study resolves the three main challenges of transferring graphene to porous substrates, which are matching the topographies between the graphene and the porous substrate, achieving high pore ratios and minimizing the stresses on the suspended graphene; this approach may therefore serve as a general guide for attaching graphene or other 2D materials to scaffold structures.