Non-covalent Modification of Graphene and MoS2 Synthesis and Characterization of Charged Molecules and Two-Dimensional Materials
Doctoral thesis, 2020
This thesis presents the synthesis of a series of neutral and charged π-conjugated systems with a different amount of either benzimidazole or pyridine moieties. The molecules differ in the size of their π-conjugated system, the amount of charges, and the counter ions. Selected molecules were used to non-covalently functionalize either graphene or molybdenum disulfide. The new two-dimensional materials were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, atomic force microscopy and Time-of-Flight secondary ion mass spectrometry. Both, neutral and charged molecules can interact with graphene/ molybdenum disulfide via intermolecular forces. Computational studies support experimental observations and helped to gain more insight about the intermolecular attraction between the π-conjugated systems and graphene. Lastly, the non-covalently functionalized graphene was used to fabricate FET-devices, which showed strong p-doping of the underlying graphene by the π-conjugated systems.
To summarize, we showed the non-covalent functionalization of graphene and molybdenum disulfide with π-conjugated molecules and the influence of structural and electrochemical parameters on the interaction with graphene or molybdenum disulfide. The results presented in this thesis can be the basis of novel sensors on the nanoscale such as a pH-meter or a humidity sensors.
charged π-conjugated systems
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4801
Chalmers University of Technology
KE lecture hall, Kemivägen 10 41296 Göteborg, Sweden
Opponent: Helena Grennberg, Uppsala University, Sweden