skip to main content

DOE PAGESDOE PAGES

Title: Iodine versus Bromine Functionalization for Bottom-Up Graphene Nanoribbon Growth: Role of Diffusion

Deterministic bottom-up approaches for synthesizing atomically well-defined graphene nanoribbons (GNRs) largely rely on the surface-catalyzed activation of selected labile bonds in a molecular precursor followed by step-growth polymerization and cyclodehydrogenation. While the majority of successful GNR precursors rely on the homolytic cleavage of thermally labile C–Br bonds, the introduction of weaker C–I bonds provides access to monomers that can be polymerized at significantly lower temperatures, thus helping to increase the flexibility of the GNR synthesis process. Scanning tunneling microscopy imaging of molecular precursors, activated intermediates, and polymers resulting from stepwise thermal annealing of both Br and I substituted precursors for chevron GNRs reveals that the polymerization of both precursors proceeds at similar temperatures on Au(111). Finally, this surprising observation is consistent with diffusion-controlled polymerization of the surface-stabilized radical intermediates that emerge from homolytic cleavage of either the C–Br or the C–I bonds.
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [2] ;  [3] ; ORCiD logo [4] ;  [5]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Physics
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
  3. Aarhus Univ. (Denmark). iNANO. Dept. of Physics and Astronomy
  4. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division. Kavli Energy NanoSciences Inst.
  5. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division. Kavli Energy NanoSciences Inst.
Publication Date:
Grant/Contract Number:
AC02-05CH11231; SC0010409; LPDS 2014-09
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 34; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Office of Naval Research (ONR) (United States); Academy of Sciences Leopoldina (Germany)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1436639