Multiply Folded Graphene

TL;DR

This paper demonstrates that controlled folding of graphene, called grafold, can be achieved experimentally and theoretically, leading to new shapes and properties, with potential for chemical intercalation and functionalization.

Contribution

It introduces the concept of grafold, showing experimental control over graphene folding and theoretical analysis of electronic modifications due to folding.

Findings

Existence of controllably folded graphene structures (grafold)

Double folding alters graphene's electronic band structure

C60 intercalation into grafolds expands their functional diversity

Abstract

The folding of paper, hide, and woven fabric has been used for millennia to achieve enhanced articulation, curvature, and visual appeal for intrinsically flat, two-dimensional materials. For graphene, an ideal two-dimensional material, folding may transform it to complex shapes with new and distinct properties. Here, we present experimental results that folded structures in graphene, termed grafold, exist, and their formations can be controlled by introducing anisotropic surface curvature during graphene synthesis or transfer processes. Using pseudopotential-density functional theory calculations, we also show that double folding modifies the electronic band structure of graphene. Furthermore, we demonstrate the intercalation of C60 into the grafolds. Intercalation or functionalization of the chemically reactive folds further expands grafold's mechanical, chemical, optical, and electronic diversity.