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Abstract
Graphene nanoribbons represent a unique class of one-dimensional carbon nanomaterials whose electronic, optical, and magnetic properties are governed by atomic-scale structural parameters, including width, edge topology, length, and chemical composition. Unlike bulk graphene, which lacks an intrinsic band gap, GNRs exhibit tunable band gaps and emergent quantum phenomena arising from lateral quantum confinement and edge effects, rendering them promising candidates for next-generation nanoelectronic and optoelectronic devices. However, the realization of these properties in functional materials critically depends on synthetic approaches capable of delivering atomically precise structures with strict control over ribbon geometry and chemical uniformity. This dissertation focuses on the bottom-up synthesis of graphene nanoribbons as a strategy to overcome the limitations of conventional top-down fabrication methods, which often suffer from structural disorder, edge roughness, and poor reproducibility. Using our own Protecting Group Assisted Iterative Synthetic (PAIS) bottom-up approach enabled the programmed construction of GNRs from rationally designed molecular precursors, allowing precise control over ribbon width, edge structure, heteroatom incorporation, and length. Both solution-phase and surface-assisted synthetic methodologies are explored, with a delicate interplay between the two methods producing interesting scaffolds not previously reported in the literature. Through the development and optimization of these synthetic routes, this work demonstrates the preparation of atomically precise armchair graphene nanoribbons with well-defined widths and narrow band gaps, as well as structurally complex architectures incorporating heterojunctions, edge modulation, and functional substituents. Comprehensive structural and electronic characterization is carried out using a combination of spectroscopic, microscopic, and computational techniques, including nuclear magnetic resonance spectroscopy, mass spectrometry, scanning tunneling microscopy, and electronic structure calculations. These studies elucidate the relationships between molecular design, on-surface reaction pathways, and the resulting electronic and optoelectronic properties of the nanoribbons.