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 cm2 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. In this work, a rapid and catalyst‐free method for the synthesis of few‐layer graphdiyne (GDY) at a solid/liquid interface using a microwave‐induced temperature gradient is reported. Under microwave irradiation, hexaethynylbenzene molecules at the surface of NaCl crystals are heated to form GDY by cross‐coupling, while the bulk solution is sufficiently cooled to ensure the stability of the monomers.