Abstracts

One-dimensional organic molecular wires have emerged as idealized model systems for investigating charge transport mechanisms at 1-10 nm length scales, where the distinction between individual molecules and bulk materials begins to vanish. However, there are significant difficulties associated with the synthesis and electronic characterization of well-defined organic molecular wires. By drawing inspiration from oligonucleotide synthesis, we have developed a facile strategy for the assembly of perylene-based organic semiconductor building blocks in predetermined arrangements on a DNA-like backbone, resulting in molecular wires which have well-defined lengths, geometries, and sequence contexts. We self-assembled monolayers of these wires onto gold substrates and investigated their charge transport properties with both electrochemical and spectroscopic techniques. We found that as we increased the number of perylene building blocks, both the electron transfer and excited-state charge transfer dynamics show unexpected trends, which we rationalize with molecular dynamics and density-functional theory. Our findings hold significance both for fundamentally understanding nanoscale charge transport phenomena and for the development of new types of biological and molecular electronic devices.