Abstract:

Organic semiconductors attract interest from the scientific community for applications in thermoelectric, optoelectronic, and bioelectronic devices, owing to their ease of processing through ink-based techniques, such as inkjet and roll-to-roll printing. However, their progress is hindered by a limited understanding of the interplay between processing conditions, host-dopant interactions, and charge transport mechanisms. This thesis aims to develop a roadmap of the interactions between molecular dopants and conjugated polymers as hosts, and the impact of such interactions on charge transport mechanisms and electronic properties, namely changes in electrical conductivity, mobility, and the Seebeck coefficient. The thesis will present phenomenological models to elucidate structure-property correlations, based on results provided by advanced imaging, spectroscopic and electronic characterization. Furthermore, the project integrates the processing conditions as a pivotal step to control the charge transport properties of doped conjugated polymers. This will allow establishing a link between molecular properties of doped conjugated polymers and the various manifestations of static disorder such as energetic and structural disorder, offering novel strategies to decouple interdependent properties such as electrical conductivity and Seebeck coefficient. With this we intend to provide a series of guidelines for the design novel CPs as well as maximizing the performance of existing CPs in energy conversion devices, particularly thermoelectrics.