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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. Lastly, theoretically predicted red shifts in absorbance were observed experimentally, as well as the expected quench in photoluminescence and lifetimes in time-resolvedmore » photoluminescence« less

Authors:
ORCiD logo; ORCiD logo; ; ; ; ;
Publication Date:
Research Org.:
Vanderbilt Univ., Nashville, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1340501
Alternate Identifier(s):
OSTI ID: 1340502; OSTI ID: 1340504
Grant/Contract Number:
AC02-05CH11231; FG02-09ER46554; ACI-1053575; EPS-1004083; CHE-1506587
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 17; Journal Issue: 2; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; CdSe/CdS nanorod; density functional theory; dithiocarbamate; Hole transfer; midgap states; hole transfer

Citation Formats

La Croix, Andrew D., O’Hara, Andrew, Reid, Kemar R., Orfield, Noah J., Pantelides, Sokrates T., Rosenthal, Sandra J., and Macdonald, Janet E. Design of a Hole Trapping Ligand. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.6b04213.
La Croix, Andrew D., O’Hara, Andrew, Reid, Kemar R., Orfield, Noah J., Pantelides, Sokrates T., Rosenthal, Sandra J., & Macdonald, Janet E. Design of a Hole Trapping Ligand. United States. doi:10.1021/acs.nanolett.6b04213.
La Croix, Andrew D., O’Hara, Andrew, Reid, Kemar R., Orfield, Noah J., Pantelides, Sokrates T., Rosenthal, Sandra J., and Macdonald, Janet E. Wed . "Design of a Hole Trapping Ligand". United States. doi:10.1021/acs.nanolett.6b04213. https://www.osti.gov/servlets/purl/1340501.
@article{osti_1340501,
title = {Design of a Hole Trapping Ligand},
author = {La Croix, Andrew D. and O’Hara, Andrew and Reid, Kemar R. and Orfield, Noah J. and Pantelides, Sokrates T. and Rosenthal, Sandra J. and Macdonald, Janet E.},
abstractNote = {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. Lastly, theoretically predicted red shifts in absorbance were observed experimentally, as well as the expected quench in photoluminescence and lifetimes in time-resolved photoluminescence},
doi = {10.1021/acs.nanolett.6b04213},
journal = {Nano Letters},
number = 2,
volume = 17,
place = {United States},
year = {Wed Jan 18 00:00:00 EST 2017},
month = {Wed Jan 18 00:00:00 EST 2017}
}

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  • Here, 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 transfermore » 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« less
  • Here, 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 transfermore » 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.« less
  • No abstract prepared.
  • The synthesis and coordination chemistry of a new asymmetric multidentate ligand designed for modeling coordination number asymmetry at metal sites in binuclear metalloproteins are described. A binuclear copper complex of this ligand demonstrates proof-of-concept for inducing coordinative unsaturation at one metal of the binuclear pair, and subsequent reaction with azide illustrates site-directed reactivity.
  • A series of tris(polypyridine)ruthenium(II) complexes (Ru(dmb)/sub 3/)/sup 2 +/, (Ru(dmb)/sub 2/(decb))/sup 2 +/, (Ru(dmb)(decb)/sub 2/)/sup 2 +/, and (Ru(decb)/sub 3/)/sup 2 +/ have been prepared, where dmb is 4,4'-dimethyl-2,2'-bipyridine and decb is 4,4'-bis(ethylcarboxy)-2,2'-bipyridine. Absorption and emission energies decrease in the order (Ru(dmb)/sub 3/)/sup 2 +/ > (Ru(decb)/sub 3/)/sup 2 +/ > (Ru(dmb)(decb)/sub 2/)/sup 2 +/ > (Ru(dmb)/sub 2/(decb))/sup 2 +/ and are linearly related to ..delta..E/sup 0/, the difference between the first oxidation and reduction potentials of the complex. Temperature-dependent emission quantum yields and lifetimes in CH/sub 2/Cl/sub 2/ yield activation barriers, ..delta..E', for nonradiative decay from the /sup 3/MLCTmore » state. For (Ru(dmb)/sub 3/)/sup 2 +/ and (Ru(decb)/sub 3/)/sup 2 +/ the ..delta..E' values are 2750 and 1180 cm/sup -1/, respectively, and represent the thermal barrier to population of a metal-centered excited state. Upon photolysis in the presence of Cl/sup -/ in Ch/sub 2/Cl/sub 2/, substitution occurs, resulting in the cis chloro complex. The mixed-ligand complexes exhibit much smaller activation barriers for nonradiative decay and do not undergo anation upon prolonged photolysis in the presence of Cl/sup -/. The nonradiative decay and photosubstitution results are discussed in terms of the energetic separation between the /sup 3/MLCT and /sup 3/MC states. 45 references, 6 figures, 6 tables.« less