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Abstract

Confining the electron wave functions of the semi-metal graphene by reducing its dimensionality leads to the opening of a bandgap. The resulting one-dimensional semiconductors like singlewalled carbon nanotubes (SWCNTs) or graphene nanoribbons (GNRs) are promising materials for optoelectronic applications, due to their outstanding carrier mobilities and structuredependent tunable optical and electronic properties. The fundamental properties of SWCNTs, such as exciton dynamics, charge transport and their interaction with their environment have been studied thoroughly over the past decades and SWCNTs have been successfully integrated into a variety of optoelectronic devices. However, practical bottlenecks, associated with dispersion, purification and processing prevent scalable device integration. This thesis provides optimized and detailed protocols to obtain high-purity dispersions of long, defect-free semiconducting (6,5), (7,5) and large diameter semiconducting SWCNTs via polymer-wrapping in organic solvents using shear force mixing as an exfoliation method. Furthermore, a new highly soluble Lewis acid-based dopant is introduced for efficient and stable p-type doping of small-diameter, polymer-wrapped SWCNTs. In contrast to SWCNTs, many of the fundamental properties of atomically-precise GNRs are still under active investigation, as they have been first synthesized almost a decade later than SWCNTs. This work demonstrates that structural defects, which are commonly introduced during bottom-up synthesis of GNRs, significantly alter absorption and emission features in dispersions of GNRs, as well as the charge transport in GNR-based field-effect transistors. A simple method to heal defects in GNR films and thus improve their charge transport properties is presented. This work also provides first evidence of polaron formation in GNRs upon introduction of excess charge carriers via chemical and electrochemical doping. The findings highlight similarities between semiconducting polymers and GNRs, both in optical response to doping and charge transport in devices. Within this thesis, these findings are contextualized within the broader research landscape and implications for future studies are discussed.