title: Design of a Hole Trapping Ligand.
abstract: A new ligand that covalently attaches to the surface of colloidal CdSe/CdS nanorods and can simultaneously chelate a molecular metal center is described. The dithiocarbamate-bipyridine ligand system facilitates hole transfer through energetic overlap at the inorganic-organic interface and conjugation through the organic ligand to a chelated metal center. Density functional theory calculations show that the coordination of the free ligand to a CdS surface causes the formation of two hybridized molecular states that lie in the band gap of CdS. The further chelation of Fe(II) to the bipyridine moiety causes the presence of seven midgap states. Hole transfer from the CdS valence band to the midgap states is dipole allowed and occurs at a faster rate than what is experimentally known for the CdSe/CdS band-edge radiative recombination. In the case of the ligand bound with iron, a two-step process emerges that places the hole on the iron, again at rates much faster than band gap recombination. The system was experimentally assembled and characterized via UV-vis absorbance spectroscopy, fluorescence spectroscopy, time-resolved photoluminescence spectroscopy, and energy dispersive X-ray spectroscopy. Theoretically predicted red shifts in absorbance were observed experimentally, as well as the expected quench in photoluminescence and lifetimes in time-resolved photoluminescence.
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Andrew D
authors.identifier: 0000-0001-5927-0003
authors.initials: AD
authors.lastname: La Croix
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Andrew
authors.identifier: 0000-0002-0323-9039
authors.initials: A
authors.lastname: O'Hara
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Kemar R
authors.initials: KR
authors.lastname: Reid
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Noah J
authors.initials: NJ
authors.lastname: Orfield
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Sokrates T
authors.initials: ST
authors.lastname: Pantelides
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Rosenthal
authors.affiliation: Department of Chemistry, ‡Department of Physics and Astronomy, §Department of Electrical Engineering and Computer Science, ∥Department of Pharmacology, ⊥Department of Chemical and Biomolecular Engineering, #Interdisciplinary Materials Science, and ∇The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Macdonald
keywords: CdSe/CdS nanorod; Hole transfer; density functional theory; dithiocarbamate; midgap states