Automated Synthesis for Single-Molecule Electronics

The development of next-generation organic electronic materials critically relies on understanding structure-function relationships in conjugated polymers. However, unlocking the full potential of organic materials requires access to their vast chemical space while efficiently managing the large synthetic workload to survey new materials. In this talk, we report the use of a new automated synthesis platform to prepare large libraries of conjugated oligomers for molecular electronic applications. Molecular libraries are designed with systematically varied backbone and side chain composition. Single-molecule charge transport measurements reveal that molecular junctions with long alkyl side chains exhibit a concentration-dependent bimodal conductance with an unexpectedly high conductance state that arises due to surface adsorption and backbone planarization. These results are supported by a series of control experiments using asymmetric, planarized, and sterically hindered molecules. Density functional theory simulations and additional control experiments using different anchors and alkoxy side chains highlight the role of side chain chemistry on charge transport. Overall, this work opens new avenues for using automated synthesis for the development of organic electronic materials.