title: Successive Ionic Layer Absorption and Reaction for Postassembly Control over Inorganic Interdot Bonds in Long-Range Ordered Nanocrystal Films.
abstract: Epitaxially connected assemblies of nanocrystals (NCs) present an interesting new class of nanomaterial in which confinement of charge carriers is intermediate between that of a quantum dot and a quantum well. Despite impressive advances in the formation of high-fidelity assemblies, predicted collective properties have not yet emerged. A critical knowledge gap toward realizing these properties is the current lack of understanding of and control over the formation of epitaxial interdot bonds connecting the NCs within the assemblies. In this work we demonstrate successive ionic layer absorption and reaction (SILAR) to enhance the interdot bonding within the NC assembly. SILAR treatment improved the fraction of interdot bonds from 82% to 91% and increased their width from 3.1 to 4.0 nm. Absorption spectra and charge transport measurements indicate that the effect of postassembly growth on quantum confinement in this system depends on the composition of the SILAR shell material. Increased NC film conductance following SILAR processing indicates that building and strengthening interdot bonds lead to increased electronic coupling and doping in the assemblies. The postassembly film growth detailed here presents an opportunity to repair structural defects and to tailor the balance of quantum confinement and interdot coupling in epitaxially connected NC assemblies.
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Treml
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Savitzky
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Ali M
authors.identifier: http://orcid.org/0000-0002-1697-0592
authors.initials: AM
authors.lastname: Tirmzi
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Jessica Cimada
authors.initials: JC
authors.lastname: DaSilva
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Lena F
authors.initials: LF
authors.lastname: Kourkoutis
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Physics, §Department of Chemistry and Chemical Biology, ∥School of Applied and Engineering Physics, ⊥Kavli Institute for Nanoscale Science, and #Robert Fredrick Smith School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Tobias
authors.identifier: http://orcid.org/0000-0001-5782-4666
authors.initials: T
authors.lastname: Hanrath
keywords: charge transport; interdot bonding; interface chemistry; nanocrystal; self-assembly