TY - JOUR
T1 - Long-Lived Photoinduced Charge Separation in a Trinuclear Iron-μ3-oxo-based Metal-Organic Framework
AU - Hanna, Lauren
AU - Kucheryavy, Pavel
AU - Liu, Cunming
AU - Zhang, Xiaoyi
AU - Lockard, Jenny V.
N1 - Funding Information:
J.V.L. acknowledges the support by the National Science Foundation under Grant No. DMR-1455127. Use of the Advanced Photon Source and the Center for Nanoscale Materials, Office of Science User Facilities operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of SSRL Beamline 2-2 is coordinated with the National Synchrotron Light Source II, Brookhaven National Laboratory under DOE Contract No. DE-SC0012704. We thank Dr. Nebojsa Marinkovic for beamline support at SSRL.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/6/29
Y1 - 2017/6/29
N2 - The presence of long-lived charge-separated excited states in metal-organic frameworks (MOFs) can enhance their photocatalytic activity by decreasing the probability that photogenerated electrons and holes recombine before accessing adsorbed reactants. Detecting these charge-separated states via optical transient absorption, however, can be challenging when they lack definitive optical signatures. We investigate the long-lived excited state of a MOF with such vague optical properties, MIL-100(Fe), composed of Fe3-μ3-oxo clusters and trimesic acid linkers, using Fe K-edge X-ray transient absorption (XTA) spectroscopy to unambiguously determine its ligand-to-metal charge-transfer character. Spectra measured at time delays up to 3.6 μs confirm the long-lived nature of the charge-separated excited state. Several trinuclear iron μ3-oxo carboxylate complexes, which model the trinuclear cores of the MOF structure, are measured for comparison using both steady-state X-ray absorption spectroscopy and XTA to further support this assignment and corresponding decay time. The MOF is prepared as a colloidal nanoparticle suspension for these measurements, so both its fabrication and particle size analysis are presented as well.
AB - The presence of long-lived charge-separated excited states in metal-organic frameworks (MOFs) can enhance their photocatalytic activity by decreasing the probability that photogenerated electrons and holes recombine before accessing adsorbed reactants. Detecting these charge-separated states via optical transient absorption, however, can be challenging when they lack definitive optical signatures. We investigate the long-lived excited state of a MOF with such vague optical properties, MIL-100(Fe), composed of Fe3-μ3-oxo clusters and trimesic acid linkers, using Fe K-edge X-ray transient absorption (XTA) spectroscopy to unambiguously determine its ligand-to-metal charge-transfer character. Spectra measured at time delays up to 3.6 μs confirm the long-lived nature of the charge-separated excited state. Several trinuclear iron μ3-oxo carboxylate complexes, which model the trinuclear cores of the MOF structure, are measured for comparison using both steady-state X-ray absorption spectroscopy and XTA to further support this assignment and corresponding decay time. The MOF is prepared as a colloidal nanoparticle suspension for these measurements, so both its fabrication and particle size analysis are presented as well.
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U2 - 10.1021/acs.jpcc.7b03936
DO - 10.1021/acs.jpcc.7b03936
M3 - Article
AN - SCOPUS:85022175049
VL - 121
SP - 13570
EP - 13576
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 25
ER -