Agradecimentos: The authors are grateful to Prof. Jessica Bickel (Cleveland State University) for discussions of scanning probe microscopy data. The authors thank the US Department of Energy (R01AB123456) and the National Science Foundation (GFRP award 1451075 to W.B.M.) for funding. R.H.B. acknowledges support from Robert A. Welch Foundation (grant AT-0029). D.S.G. and A.F.F. acknowledge support from São Paulo Research Foundation (FAPESP, awards #2013/08293-7 and #2020/02044-9), National Council for Scientific and Technological Development (CNPq), and the John David Rogers Computing Center (CCJDR) at the Institute of Physics "Gleb Wataghin", University of Campinas. The authors thank Oxford Instruments Asylum Research for providing access to Cypher VRS AFM instrument. This work made use of the High Performance Computing Resource in the Core Facility for Advanced Research Computing at Case Western Reserve University. Raman spectroscopy was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-2026822. The use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract DE-AC02-76SF00515 Ver menos

Abstract: gamma-Graphyne is the most symmetric sp(2)/sp(1) allotrope of carbon, which can be viewed as graphene uniformly expanded through the insertion of two-carbon acetylenic units between all the aromatic rings. To date, synthesis of bulk gamma-graphyne has remained a challenge. We here report the synthesis of multilayer gamma-graphyne through crystallization-assisted irreversible cross-coupling polymerization. A comprehensive characterization of this new carbon phase is described, including synchrotron powder X-ray diffraction, electron diffraction, lateral force microscopy, Raman spectroscopy, infrared spectroscopy, and cyclic voltammetry. Experiments indicate that gamma-graphyne is a 0.48 eV band gap semiconductor, with a hexagonal a-axis spacing of 6.88 angstrom and an interlayer spacing of 3.48 angstrom, which is consistent with theoretical predictions. The observed crystal structure has an aperiodic sheet stacking. The material is thermally stable up to 240 degrees C but undergoes transformation at higher temperatures. While conventional 2D polymerization and reticular chemistry rely on error correction through reversibility, we demonstrate that a periodic covalent lattice can be synthesized under purely kinetic control. The reported methodology is scalable and inspires extension to other allotropes of the graphyne family Ver menos