Bromination of graphene and graphite

Yaya, A. and Ewels, C. and Suarez-Martinez, I. and Wagner, Ph. and Lefrant, S. and Okotrub, A. and Bulusheva, L. and Briddon, P.R. 2011. Bromination of graphene and graphite. Physical Review B. 83: pp. 045411-1-045411-5.

Source Title

Physical Review B

DOI

10.1103/PhysRevB.83.045411

ISSN

10980121

School

Nanochemistry Research Institute (Research Institute)

URI

http://hdl.handle.net/20.500.11937/20613

Collection

Curtin Research Publications

Abstract

We present a density-functional theory study of low-density bromination of graphene and graphite, finding significantly different behavior in these two materials. In graphene, we find a new Br2 form where the molecule sits perpendicular to the graphene sheet with an extremely strong molecular dipole. The resultant Br+-Br- has an empty pz orbital located in the graphene electronic π cloud. Bromination opens a small (86-meV) band gap and strongly dopes the graphene. In contrast, in graphite, we find Br2 is most stable parallel to the carbon layers with a slightly weaker associated charge transfer and no molecular dipole. We identify a minimum stable Br2 concentration in graphite, finding low-density bromination to be endothermic. Graphene may be a useful substrate for stabilizing normally unstable transient molecular states.