Scalable Synthesis and Characterization of Multilayer gamma-Graphyne, New Carbon Crystals with a Small Direct Band Gap

Author(s):Show less -

Desyatkin, Victor G. ; Martin, William B. ; Aliev, Ali E. ; Chapman, Nathaniel E. ; Fonseca, Alexandre F. ; Galvao, Douglas S. ; Miller, Ericka Roy ; Stone, Kevin H. ; Wang, Zhong ; Zakhidov, Dante ; Limpoco, F. Ted ; Almahdali, Sarah R. ; Parker, Shane M. ; Baughman, Ray H. ; Rodionov, Valentin O.

• Document type: Journal article
• Source: Journal of the American Chemical Society; v. 144, n. 39, p. 10-pg., 2022-09-21.

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. (AU)

• FAPESP's process: 20/02044-9 - Modeling and simulation of physical properties of materials
• Grantee: Alexandre Fontes da Fonseca
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC