Catalyst-Free Synthesis of Few-Layer Graphdiyne Using a Microwave-Induced Temperature Gradient at a Solid/Liquid Interface

Graphdiyne (GDY), a 2D carbon allotrope, is predicted to possess high carrier mobility and an intrinsic bandgap. However, the controlled synthesis of mono- or few-layer GDY with good crystallinity remains challenging because of the instability of the monomers. Herein, a rapid and catalyst-free synthetic method is presented for few-layer GDY involving the use of a solid/liquid interface and a microwave-induced temperature gradient. Sodium chloride, which can absorb microwave energy, is used as the solid substrate in a nonabsorbing solvent. A temperature gradient is formed at the solid/liquid interface under microwave irradiation, facilitating the cross-coupling reaction of monomers at the solid surface and stabilizing the monomers in the bulk solution. Few-layer GDY with an average thickness of less than 2 nm, a field-effect mobility of 50.1 cm(2) V-1 s(-1), and p-type characteristics is successfully obtained. This wet chemical approach may be extended to the synthesis of other few-layered 2D materials with improved quality.