| Summary: | <p>This thesis presents an exploration of new opportunities offered by employing porphyrins as functional units in molecular electronic tasks, with a focus on their conducting behavior.</p>
<p><strong>Chapter 1</strong> reviews the charge-transport characteristics of organic oligomeric structures (including hydrocarbon chains and porphyrin-based structures) evaluated as molecular wire candidates, with a focus on their single-molecule conductance behavior.</p>
<p><strong>Chapter 2</strong> proposes a design of molecular geometric switch consisting of porphyrin and paraquat as main functioning units, aiming at creating two hysteretic conductance states in a single molecule to serve as a memory device. A conceptual porphyrin-paraquat conjugate was synthesized for single-molecule conductance study using the STM-BJ technique. While the preliminary conductance results showed that the interaction between porphyrin and paraquat can induce a change in the single-molecule conductance, the switching within one molecule could not be detected.</p>
<p><strong>Chapter 3</strong> presents a theoretical and synthetic exploration of a one-dimensionally extended fully fused anthracene-porphyrin hetero-oligomer structure. The successful preparation of short anthracene-porphyrin nanoribbons offers a scaffold as a new molecular wire candidate, reminiscent of a heteroatom-doped GNR. The extension of the structure was investigated on a bisanthracene-linked porphyrin system but has yet to be synthetically realized.</p>
<p><strong>Chapter 4</strong> studies the intrinsic charge carrier character of triply fused porphyrin oligomers using noncontact optical-pump THz probe spectroscopy. With a series of polydisperse Ni(II) porphyrin nanoribbons, we demonstrated the strong length-dependent charge carrier mobility in this system. In extremely long and deformation-free ribbons, our results indicate that they are expected to have some of the highest intrinsic carrier mobilities among the known GNRs.</p>
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