Session: Physical Chemistry Poster:

Understanding the effect of side chains is crucial for designing new polymeric materials for organic electronics with improved properties and device performance. Prior work has mainly focused on measuring the electronic properties of conjugated organics with different chemical side chains at the macroscopic scale. Despite recent progress, we lack a full understanding of the effect of side chain chemistry on the charge transport properties of these materials at the molecular scale. In this work, we study the charge transport behavior of terphenyl molecular junctions by systematically varying alkyl side chain lengths and conjugation position using a combination of automated chemical synthesis and single molecule charge transport experiments. Our results show that long alkyl side chains facilitate the adsorption of the main chain backbone to an electrode surface, induce planarization, and enhance molecular conductance. Density functional theory simulations and control experiments with different chemical anchors and solvents are used to directly complement experiments and further support our findings. Overall, this work will open new avenues to use automated synthesis approach for molecular engineering of chemical side chains and designing functional molecular electronic devices.

Jeffrey S. Moore

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