Ultrafast growth of nanocrystalline graphene films by quenching and grain-size-dependent strength and bandgap opening.

ABSTRACT: Nanocrystallization is a well-known strategy to dramatically tune the properties of materials; however, the grain-size effect of graphene at the nanometer scale remains unknown experimentally because of the lack of nanocrystalline samples. Here we report an ultrafast growth of graphene films within a few seconds by quenching a hot metal foil in liquid carbon source. Using Pt foil and ethanol as examples, four kinds of nanocrystalline graphene films with average grain size of ~3.6, 5.8, 8.0, and 10.3?nm are synthesized. It is found that the effect of grain boundary becomes more pronounced at the nanometer scale. In comparison with pristine graphene, the 3.6?nm-grained film retains high strength (101?GPa) and Young's modulus (576?GPa), whereas the electrical conductivity is declined by over 100 times, showing semiconducting behavior with a bandgap of ~50?meV. This liquid-phase precursor quenching method opens possibilities for ultrafast synthesis of typical graphene materials and other two-dimensional nanocrystalline materials.

SUBMITTER: Zhao T 

PROVIDER: S-EPMC6813332 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature