Macroscopic, Freestanding, and Tubular Graphene Architectures Fabricated <i>via</i> Thermal Annealing

Abstract

Manipulation of individual graphene sheets/films into specific architectures at macroscopic scales is crucially important for practical uses of graphene. We present herein a versatile and robust method based on annealing of solid carbon precursors on nickel templates and thermo-assisted removal of poly(methyl methacrylate) under low vacuum of ∼0.6 Pa for fabrication of macroscopic, freestanding, and tubular graphene (TG) architectures. Specifically, the TG architectures can be obtained as individual and woven tubes with a diameter of ∼50 μm, a wall thickness in the range of 2.1–2.9 nm, a density of ∼1.53 mg·cm^–3, a thermal stability up to 600 °C in air, an electrical conductivity of ∼1.48 × 10⁶ S·m^–1, and field emission current densities on the order of 10⁴ A·cm^–2 at low applied electrical fields of 0.6–0.7 V·μm^–1. These properties show great promise for applications in flexible and lightweight electronics, electron guns, or X-ray tube sources