Draadloze elektrochemische methoden voor de exfoliatie en functionalisering van tweedimensionale materialen

Following graphene's discovery, two-dimensional (2D) materials have attracted tremendous scientific interest due to their remarkable anticipated properties. The expanding catalog of theoretically predicted 2D materials presents materials with properties that approach but do not precisely match application requirements, highlighting the critical need for strategic modification strategies. Rather than being constrained by intrinsic material characteristics, desired functionalities can be engineered through targeted functionalization, expanding the accessible property landscape of 2D systems. While covalent functionalization approaches offer pathways to tailor and enhance these characteristics for broader application integration, current methodologies impose significant limitations that restrict their practical implementation. These conventional techniques demand harsh reaction conditions without providing adequate control over functionalization density or surface homogeneity. Furthermore, established approaches fail completely when applied to non-conductive materials, as they fundamentally depend on charge transfer mechanisms that cannot operate in insulating systems. Therefore, the research landscape beyond graphene remains underdeveloped, with limited investigation into the functionalization of other 2D material classes. This thesis overcomes these limitations and addresses the challenges to the development of a universal strategy applicable to all electronic classes of 2D materials. To this end, a wireless electrochemical methodology is implemented, capable of simultaneous exfoliation and covalent functionalization of layered materials across all electronic classes. The requirement for direct electrical connections is eliminated by the bipolar approach, enabling processing of non-conductive materials while operating entirely in aqueous media without surfactants or toxic solvents. The research systematically establishes optimal molecular precursors through comparative analysis of aryl amines and diazonium salts, revealing superior grafting performance of diazonium chemistry. Parameter optimization using substrates fabricated using chemical vapor deposition (CVD) methods was performed to access precise control over functionalization density and distribution in wireless configurations. The methodology's universal applicability is validated through successful implementation across semimetallic (graphene), semiconducting (molybdenum disulfide, MoS2), and dielectric (hexagonal boron nitride, hBN) material systems. For graphene, the protocol yields predominantly single-layer flakes with lateral dimensions significantly exceeding conventional liquid-phase methods while maintaining structural integrity. Extension to MoS2 demonstrates versatility across material classes, with cascade centrifugation enabling size selection for uniform thin film fabrication. The successful functionalization of hBN represents the first reported covalent grafting of this chemically inert material using diazonium chemistry, establishing a previously inaccessible modification pathway for dielectric 2D materials. Comprehensive characterization across multiple analytical techniques, including atomic force microscopy (AFM), statistical Raman mapping and X-ray Photoelectron Spectroscopy (XPS) confirms both effective exfoliation and successful functionalization for all material systems. The approach enables fundamental property modification, demonstrated through the induction of measurable electrical conductivity in inherently insulating hBN. Comparative analysis with conventional methods reveals mechanistic advantages, including independence between layer thickness and lateral dimensions that enables production of high-quality monolayers with exceptional aspect ratios.