Self-Organized Graphene Nanosheets with Corrugated, Ordered Tip Structures for High-Performance Flexible Field Emission

Patterned reduced graphene oxide (rGO) films with vertically aligned tip structures are fabricated by a straightforward self‐assembly method. The size, uniformity of the patterns, and alignment of the tips are successfully controlled according to the concentration of a GO/octadecylamine (ODA)‐dispersed solution. The surface energy difference between the GO/ODA solution and a self‐assembled water droplet is a critical parameter for determining the pattern structure. Numerous rGO nanosheets are formed so as to be vertically aligned with respect to the substrate during film fabrication at GO concentrations below 2.0 g/L. These samples provide high field‐emission characteristics. The patterned rGO arrays are highly flexible with preservation of the field emission properties, even at large bending angles. This is attributed to the high crystallinity, emitter density, and good chemical stability of the rGO arrays, as well as the strong interactions between the rGO arrays and the substrate. Self‐organized graphene nanosheets with corrugated, ordered tip structures ae fabricated by a straightforward self‐assembly method. The size, uniformity of the arrays, and alignment of tips are successfully controlled by the viscosity of the graphene oxide/octadecylamine solution. The vertically aligned tip structures of graphene thin films fabricated on polymeric substrate show excellent field emission characteristics upon bending.