  A graphyne (GY) family composed of the triple (sp) and double (sp2)
bonds-hybridized carbon atoms is a promising allotrope of carbon for the
development of nanoscale electronic devices. Unlike graphene, the GY family
containing carbon sp bonds remains an unsolved problem in efficient
two-dimensional (2D) growth due to monomer instability and side reactions.
Herein, we synthesize GY into a single 2D layer by chemical vapor deposition
(CVD) at low temperatures preventing unexpected reactions, using
1,3,5-tribromo-2,4,6-triethynylbenzene (TBTEB). The CVD-grown GY via a
surface-confined coupling between TBTEB monomers on a copper surface can be rid
of either one-dimensional (1D) or three-dimensional (3D) growths via side
reactions. The CVD-grown GY exhibits a hexagonal lattice structure containing a
single sp-carbon bond in a link between two adjacent hexagons, consisting with
the structure of gamma-GY. This work opens a new avenue for synthesizing
large-scale and single-crystalline GY that can be capable of versatile
applications with theoretically expected properties.
