Chemistry of Graphene Nanoribbons

• Applicant: Professor Dr. Siegfried Eigler
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 249559513

We firstly prepared structurally intact graphene, with a minimum of defects, from graphene oxide (GO). Now we want to increase the properties of this graphene by preventing few more defects. Systematic studies on the graphene quality and the structure of GO in dependence on the graphite type, morphology, existing defect density, amount of oxidant and especially the temperature of the process will be done.The reduction with different reducing methods and their influence on the defect density can now be examined for the first time and should lead to a ranking of reducing agents for GO. Another focus is on the analysis of residual defects, as well as the purity of the surfaces. The resulting material is used to build transparent and electrically conductive layers.Using field-effect transistors, the properties of the graphene will be modulated to open a band gap in graphene. We are mostly interested in non-covalent approaches.The non-destructive chemical functionalization of GO is essential for building high-performance graphene architectures. Defects must be avoided to use the full potential of graphene. With our improved graphene, it is possible to study chemical reactions and their effect on the resulting graphene quality. Information on the stability of the carbon skeleton as in acidic or basic medium can be investigated to identify reaction conditions that allow further non-destructive functionalization of GO.The azide-functionalized GO recently manufactured by us is so far the only example of a non-destructive functionalization of GO. Therefore, the reactivity of GO will be examined in depth, including towards halides and pseudo halides to provide a broader chemistry.Moreover, it will firstly be possible to gain new insights into the chemical structure of GO with different defect density with the help of solid-state NMR studies of 15N-labeled azido-GO. Another goal will be to increase the degree of functionalization of GO with azide. For this purpose, methods are being developed to activate GO. Subsequent reactions, such as click reactions will be studied under mild conditions for the first time. These materials provide a wide follow-up chemistry and will be tested in first trials for composite materials.A particular goal in the final phase of the project will be to use GO for energy storage. Such systems have great potential in terms of mobile applications, as well as electric vehicles.

• DFG Programme: Research Grants