Two-dimensional (2D) carbon nanostructures, including graphene and carbon nanosheets are of high interest for fundamental studies of the physics of organic electronic materials for novel types of nanocomposites or nanomembranes, as well as for use in capacitors, actuators, and sensors. The direct access to tailored, dispersible materials with controlled surface chemistry, however, is impeded by the typical methods of preparation using either exfoliation techniques or high-energy processes. Here, we report direct access at room temperature to functional carbon nanosheets of uniform thickness. The novel approach is based on the self-assembly and subsequent carbonisation of a hexayne amphiphile at the soft air/water interface. The monolayer has been characterized by X-ray techniques and Infrared spectroscopy. All these experiments confirmed unambiguously the presence of a monolayer of the hexayne amphiphile that comprised a densely packed array with the alkyl chains in an ordered all-trans state. The monolayer exhibited a thickness of 2.6 nm and tilt angles of 62° and 35° for the hexayne and dodecyl segments, respectively. Most importantly, the very tight packing of the reactive hexayne segments leads to a whole series of close carbon–carbon short contacts in a less than 7 Å thick ‘carbon precursor’ sublayer. Subsequent ultraviolet irradiation of the films resulted in complete carbonisation of the molecular precursors at room temperature to produce sp2-rich carbon nanosheets with a carbon microstructure that resembled amorphous carbon materials typically obtained after annealing at temperatures above 800 °C. In this way, we produced mechanically stable and rigid functionalised carbon films that bear similarities to reduced graphene oxide, with a molecularly defined overall thickness of 1.9 nm and lateral dimensions on the order of centimetres that are, presumably, only limited by the dimensions of the Langmuir trough.
brezesinski@mpikg.mpg.de
