Ultrafast excited-state dynamics of Re(CO)3Cl(dcbpy) in solution and on nanocrystalline TiO2 and ZrO2 thin films

Yongqiang Wang, John B. Asbury, Tianquan Lian

Research output: Contribution to journalArticle

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Abstract

The excited-state dynamics of Re(CO)3Cl(dcbpy) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) in dimethyl formamide (DMF) solution and on the surface of ZrO2 and TiO2 nanocrystalline thin films were studied using femtosecond IR spectroscopy. For Re(CO)3Cl(dcbpy) in DMF solution, a long-lived metal-to-ligand charge-transfer (MLCT) state with a lifetime of > 1 nsec was observed after 400-nm excitation of the MLCT band. The frequencies for the CO stretching bonds were blue-shifted compared with those in the ground state, which was consistent with the MLCT nature of the excited state. Rapid spectral evolution of the excited-state CO stretching bands was observed within the first 12 psec. For Re(CO)3Cl(dcbpy) on ZrO2 thin films, a similar MLCT state was observed. However, the spectral blue shift was much less pronounced and occurred on a faster time scale. Vibrational relaxation was suggested as the primary contribution to the spectral evolution of Re(CO)3Cl(dcbpy) on the ZrO2 films, whereas both vibrational relaxation and solvation of the MLCT state contributed to the spectral evolution in DMF solution. The excited-state decay rate of Re(CO)3Cl(dcbpy) on ZrO2 films was faster than the rate in DMF and increased with higher excitation power. Broad mid-IR absorption of injected electrons was observed for Re(CO)3Cl(dcbpy)-sensitized TiO2 thin films. The rise time of the electron absorption signal in TiO2 was < 100 fsec. The adsorbate CO stretching bands and the detailed information about the electron-injection process that can be obtained from the adsorbate vibrational spectra were also discussed.

Original languageEnglish (US)
Pages (from-to)4291-4299
Number of pages9
JournalJournal of Physical Chemistry A
Volume104
Issue number18
DOIs
StatePublished - May 11 2000

Fingerprint

Carbon Monoxide
Excited states
Thin films
charge transfer
thin films
ligands
Charge transfer
Dimethylformamide
excitation
Metals
metals
Ligands
molecular relaxation
Stretching
Adsorbates
electrons
Electron absorption
blue shift
vibrational spectra
decay rates

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

@article{d05dded859084a65a2813cf2c0caa165,
title = "Ultrafast excited-state dynamics of Re(CO)3Cl(dcbpy) in solution and on nanocrystalline TiO2 and ZrO2 thin films",
abstract = "The excited-state dynamics of Re(CO)3Cl(dcbpy) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) in dimethyl formamide (DMF) solution and on the surface of ZrO2 and TiO2 nanocrystalline thin films were studied using femtosecond IR spectroscopy. For Re(CO)3Cl(dcbpy) in DMF solution, a long-lived metal-to-ligand charge-transfer (MLCT) state with a lifetime of > 1 nsec was observed after 400-nm excitation of the MLCT band. The frequencies for the CO stretching bonds were blue-shifted compared with those in the ground state, which was consistent with the MLCT nature of the excited state. Rapid spectral evolution of the excited-state CO stretching bands was observed within the first 12 psec. For Re(CO)3Cl(dcbpy) on ZrO2 thin films, a similar MLCT state was observed. However, the spectral blue shift was much less pronounced and occurred on a faster time scale. Vibrational relaxation was suggested as the primary contribution to the spectral evolution of Re(CO)3Cl(dcbpy) on the ZrO2 films, whereas both vibrational relaxation and solvation of the MLCT state contributed to the spectral evolution in DMF solution. The excited-state decay rate of Re(CO)3Cl(dcbpy) on ZrO2 films was faster than the rate in DMF and increased with higher excitation power. Broad mid-IR absorption of injected electrons was observed for Re(CO)3Cl(dcbpy)-sensitized TiO2 thin films. The rise time of the electron absorption signal in TiO2 was < 100 fsec. The adsorbate CO stretching bands and the detailed information about the electron-injection process that can be obtained from the adsorbate vibrational spectra were also discussed.",
author = "Yongqiang Wang and Asbury, {John B.} and Tianquan Lian",
year = "2000",
month = "5",
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pages = "4291--4299",
journal = "Journal of Physical Chemistry A",
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publisher = "American Chemical Society",
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}

Ultrafast excited-state dynamics of Re(CO)3Cl(dcbpy) in solution and on nanocrystalline TiO2 and ZrO2 thin films. / Wang, Yongqiang; Asbury, John B.; Lian, Tianquan.

In: Journal of Physical Chemistry A, Vol. 104, No. 18, 11.05.2000, p. 4291-4299.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ultrafast excited-state dynamics of Re(CO)3Cl(dcbpy) in solution and on nanocrystalline TiO2 and ZrO2 thin films

AU - Wang, Yongqiang

AU - Asbury, John B.

AU - Lian, Tianquan

PY - 2000/5/11

Y1 - 2000/5/11

N2 - The excited-state dynamics of Re(CO)3Cl(dcbpy) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) in dimethyl formamide (DMF) solution and on the surface of ZrO2 and TiO2 nanocrystalline thin films were studied using femtosecond IR spectroscopy. For Re(CO)3Cl(dcbpy) in DMF solution, a long-lived metal-to-ligand charge-transfer (MLCT) state with a lifetime of > 1 nsec was observed after 400-nm excitation of the MLCT band. The frequencies for the CO stretching bonds were blue-shifted compared with those in the ground state, which was consistent with the MLCT nature of the excited state. Rapid spectral evolution of the excited-state CO stretching bands was observed within the first 12 psec. For Re(CO)3Cl(dcbpy) on ZrO2 thin films, a similar MLCT state was observed. However, the spectral blue shift was much less pronounced and occurred on a faster time scale. Vibrational relaxation was suggested as the primary contribution to the spectral evolution of Re(CO)3Cl(dcbpy) on the ZrO2 films, whereas both vibrational relaxation and solvation of the MLCT state contributed to the spectral evolution in DMF solution. The excited-state decay rate of Re(CO)3Cl(dcbpy) on ZrO2 films was faster than the rate in DMF and increased with higher excitation power. Broad mid-IR absorption of injected electrons was observed for Re(CO)3Cl(dcbpy)-sensitized TiO2 thin films. The rise time of the electron absorption signal in TiO2 was < 100 fsec. The adsorbate CO stretching bands and the detailed information about the electron-injection process that can be obtained from the adsorbate vibrational spectra were also discussed.

AB - The excited-state dynamics of Re(CO)3Cl(dcbpy) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) in dimethyl formamide (DMF) solution and on the surface of ZrO2 and TiO2 nanocrystalline thin films were studied using femtosecond IR spectroscopy. For Re(CO)3Cl(dcbpy) in DMF solution, a long-lived metal-to-ligand charge-transfer (MLCT) state with a lifetime of > 1 nsec was observed after 400-nm excitation of the MLCT band. The frequencies for the CO stretching bonds were blue-shifted compared with those in the ground state, which was consistent with the MLCT nature of the excited state. Rapid spectral evolution of the excited-state CO stretching bands was observed within the first 12 psec. For Re(CO)3Cl(dcbpy) on ZrO2 thin films, a similar MLCT state was observed. However, the spectral blue shift was much less pronounced and occurred on a faster time scale. Vibrational relaxation was suggested as the primary contribution to the spectral evolution of Re(CO)3Cl(dcbpy) on the ZrO2 films, whereas both vibrational relaxation and solvation of the MLCT state contributed to the spectral evolution in DMF solution. The excited-state decay rate of Re(CO)3Cl(dcbpy) on ZrO2 films was faster than the rate in DMF and increased with higher excitation power. Broad mid-IR absorption of injected electrons was observed for Re(CO)3Cl(dcbpy)-sensitized TiO2 thin films. The rise time of the electron absorption signal in TiO2 was < 100 fsec. The adsorbate CO stretching bands and the detailed information about the electron-injection process that can be obtained from the adsorbate vibrational spectra were also discussed.

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