title: Confined-but-connected quantum solids via controlled ligand displacement.
abstract: Confined-but-connected quantum dot solids (QDS) combine the advantages of tunable, quantum-confined energy levels with efficient charge transport through enhanced electronic interdot coupling. We report the fabrication of QDS by treating self-assembled films of colloidal PbSe quantum dots with polar nonsolvents. Treatment with dimethylformamide balances the rates of self-assembly and ligand displacement to yield confined-but-connected QDS structures with cubic ordering and quasi-epitaxial interdot connections through facets of neighboring dots. The QDS structure was analyzed by a combination of transmission electron microscopy and wide-angle and small-angle X-ray scattering. Excitonic absorption signatures in optical spectroscopy confirm that quantum confinement is preserved. Transport measurements show significantly enhanced conductivity in treated films.
authors.affiliation: Department of Chemistry and Chemical Biology, ‡Department of Materials Science and Engineering, and §School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14850, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Baumgardner
authors.forename: Kevin
authors.initials: K
authors.lastname: Whitham
authors.forename: Tobias
authors.initials: T
authors.lastname: Hanrath