By Josh Perry, Editor [email protected]
Researchers from Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg (Germany) demonstrated a method for forming nanographene on metal oxides, which has hampered previous attempts at using graphene in nanoelectronics.
The desired nanographenes form like dominoes via cyclodehydrofluorination on the titanium oxide surface. (FAU/Konstantin Amsharov)
According to a report from FAU, metal oxides are less chemically reactive than standard metal surfaces, which makes the synthesis of graphene difficult. Previously, high temperatures were needed to make the process work.
“The researchers’ method involves using a carbon fluorine bond, which is the strongest carbon bond, the article explained. “It is used to trigger a multilevel process. The desired nanographenes form like dominoes via cyclodehydrofluorination on the titanium oxide surface.”
The carbon-carbon bonds follow suit like a zipper closing. By modifying the arrangement of the preliminary molecules, scientists can define the shape of the nanographene. The bonds form wherever the fluorine atoms are placed.
“For the first time, these research results demonstrate how carbon-based nanostructures can be manufactured by direct synthesis on the surfaces of technically-relevant semi-conducting or insulating surfaces,” the article concluded.
The research was recently published in Science. The abstract stated:
“The rational synthesis of nanographenes and carbon nanoribbons directly on nonmetallic surfaces has been an elusive goal for a long time. We report that activation of the carbon (C)–fluorine (F) bond is a reliable and versatile tool enabling intramolecular aryl-aryl coupling directly on metal oxide surfaces.
“A challenging multistep transformation enabled by C–F bond activation led to a dominolike coupling that yielded tailored nanographenes directly on the rutile titania surface. Because of efficient regioselective zipping, we obtained the target nanographenes from flexible precursors. Fluorine positions in the precursor structure unambiguously dictated the running of the ‘zipping program,’ resulting in the rolling up of oligophenylene chains.
“The high efficiency of the hydrogen fluoride zipping makes our approach attractive for the rational synthesis of nanographenes and nanoribbons directly on insulating and semiconducting surfaces.”
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