Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution

Fabrizio Messina, Andrea Cannizzo, Etienne Baranoff, Fabrizio Messina, Olivier Bräm, Mohammad Khaja Nazeeruddin, Majed Chergui

Risultato della ricerca: Article

22 Citazioni (Scopus)

Abstract

We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)3 (Os1) and Os(bpy)2(dpp) (Os2) in ethanol, where dmbp is 4,4′-dimethyl-2,2′-biypridine, bpy is 2,2′-biypridine, and dpp is 2,3- dipyridyl pyrazine. In both cases, the steady-state phosphorescence is due to the lowest 3MLCT state, whose quantum yield we estimate to be ≤5.0 × 10−3. For Os1, the steady-state phosphorescence lifetime is 25 ns. In both complexes, the photoluminescence excitation spectra map the absorption spectrum, pointing to an excitation wavelength-independent quantum yield. The ultrafast studies revealed a short-lived (≤100 fs) fluorescence, which stems from the lowest singlet metal-to-ligand-charge-transfer (1MLCT) state and decays by intersystem crossing to the manifold of 3MLCT states. In addition, Os1 exhibits a 50 ps lived emission from an intermediate triplet state at an energy ∼2000 cm−1 above that of the long-lived (25 ns) phosphorescence. In Os2, the 1MLCT−3MLCT intersystem crossing is faster than that in Os1, and no emission from triplet states is observed other than the lowest one. These observations are attributed to a higher density of states or a smaller energy spacing between them compared with Os1. They highlight the importance of the energetics on the rate of intersystem crossing.
Lingua originaleEnglish
pagine (da-a)15958-15966
Numero di pagine9
RivistaJOURNAL OF PHYSICAL CHEMISTRY. C
Volume117
Stato di pubblicazionePublished - 2013

Fingerprint

Osmium
Phosphorescence
osmium
phosphorescence
Quantum yield
Pyrazines
pyrazines
Emission spectroscopy
Absorption spectroscopy
stems
spectroscopy
atomic energy levels
Charge transfer
Absorption spectra
Photoluminescence
absorption spectroscopy
Ethanol
ethyl alcohol
Metals
Fluorescence

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Energy(all)

Cita questo

Messina, F., Cannizzo, A., Baranoff, E., Messina, F., Bräm, O., Nazeeruddin, M. K., & Chergui, M. (2013). Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution. JOURNAL OF PHYSICAL CHEMISTRY. C, 117, 15958-15966.

Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution. / Messina, Fabrizio; Cannizzo, Andrea; Baranoff, Etienne; Messina, Fabrizio; Bräm, Olivier; Nazeeruddin, Mohammad Khaja; Chergui, Majed.

In: JOURNAL OF PHYSICAL CHEMISTRY. C, Vol. 117, 2013, pag. 15958-15966.

Risultato della ricerca: Article

Messina, F, Cannizzo, A, Baranoff, E, Messina, F, Bräm, O, Nazeeruddin, MK & Chergui, M 2013, 'Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution', JOURNAL OF PHYSICAL CHEMISTRY. C, vol. 117, pagg. 15958-15966.
Messina F, Cannizzo A, Baranoff E, Messina F, Bräm O, Nazeeruddin MK e altri. Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution. JOURNAL OF PHYSICAL CHEMISTRY. C. 2013;117:15958-15966.
Messina, Fabrizio ; Cannizzo, Andrea ; Baranoff, Etienne ; Messina, Fabrizio ; Bräm, Olivier ; Nazeeruddin, Mohammad Khaja ; Chergui, Majed. / Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution. In: JOURNAL OF PHYSICAL CHEMISTRY. C. 2013 ; Vol. 117. pagg. 15958-15966.
@article{f03de144511b45959624e1e799ab749e,
title = "Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution",
abstract = "We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)3 (Os1) and Os(bpy)2(dpp) (Os2) in ethanol, where dmbp is 4,4′-dimethyl-2,2′-biypridine, bpy is 2,2′-biypridine, and dpp is 2,3- dipyridyl pyrazine. In both cases, the steady-state phosphorescence is due to the lowest 3MLCT state, whose quantum yield we estimate to be ≤5.0 × 10−3. For Os1, the steady-state phosphorescence lifetime is 25 ns. In both complexes, the photoluminescence excitation spectra map the absorption spectrum, pointing to an excitation wavelength-independent quantum yield. The ultrafast studies revealed a short-lived (≤100 fs) fluorescence, which stems from the lowest singlet metal-to-ligand-charge-transfer (1MLCT) state and decays by intersystem crossing to the manifold of 3MLCT states. In addition, Os1 exhibits a 50 ps lived emission from an intermediate triplet state at an energy ∼2000 cm−1 above that of the long-lived (25 ns) phosphorescence. In Os2, the 1MLCT−3MLCT intersystem crossing is faster than that in Os1, and no emission from triplet states is observed other than the lowest one. These observations are attributed to a higher density of states or a smaller energy spacing between them compared with Os1. They highlight the importance of the energetics on the rate of intersystem crossing.",
author = "Fabrizio Messina and Andrea Cannizzo and Etienne Baranoff and Fabrizio Messina and Olivier Br{\"a}m and Nazeeruddin, {Mohammad Khaja} and Majed Chergui",
year = "2013",
language = "English",
volume = "117",
pages = "15958--15966",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",

}

TY - JOUR

T1 - Ultrafast Relaxation Dynamics of Osmium−Polypyridine Complexes in Solution

AU - Messina, Fabrizio

AU - Cannizzo, Andrea

AU - Baranoff, Etienne

AU - Messina, Fabrizio

AU - Bräm, Olivier

AU - Nazeeruddin, Mohammad Khaja

AU - Chergui, Majed

PY - 2013

Y1 - 2013

N2 - We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)3 (Os1) and Os(bpy)2(dpp) (Os2) in ethanol, where dmbp is 4,4′-dimethyl-2,2′-biypridine, bpy is 2,2′-biypridine, and dpp is 2,3- dipyridyl pyrazine. In both cases, the steady-state phosphorescence is due to the lowest 3MLCT state, whose quantum yield we estimate to be ≤5.0 × 10−3. For Os1, the steady-state phosphorescence lifetime is 25 ns. In both complexes, the photoluminescence excitation spectra map the absorption spectrum, pointing to an excitation wavelength-independent quantum yield. The ultrafast studies revealed a short-lived (≤100 fs) fluorescence, which stems from the lowest singlet metal-to-ligand-charge-transfer (1MLCT) state and decays by intersystem crossing to the manifold of 3MLCT states. In addition, Os1 exhibits a 50 ps lived emission from an intermediate triplet state at an energy ∼2000 cm−1 above that of the long-lived (25 ns) phosphorescence. In Os2, the 1MLCT−3MLCT intersystem crossing is faster than that in Os1, and no emission from triplet states is observed other than the lowest one. These observations are attributed to a higher density of states or a smaller energy spacing between them compared with Os1. They highlight the importance of the energetics on the rate of intersystem crossing.

AB - We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)3 (Os1) and Os(bpy)2(dpp) (Os2) in ethanol, where dmbp is 4,4′-dimethyl-2,2′-biypridine, bpy is 2,2′-biypridine, and dpp is 2,3- dipyridyl pyrazine. In both cases, the steady-state phosphorescence is due to the lowest 3MLCT state, whose quantum yield we estimate to be ≤5.0 × 10−3. For Os1, the steady-state phosphorescence lifetime is 25 ns. In both complexes, the photoluminescence excitation spectra map the absorption spectrum, pointing to an excitation wavelength-independent quantum yield. The ultrafast studies revealed a short-lived (≤100 fs) fluorescence, which stems from the lowest singlet metal-to-ligand-charge-transfer (1MLCT) state and decays by intersystem crossing to the manifold of 3MLCT states. In addition, Os1 exhibits a 50 ps lived emission from an intermediate triplet state at an energy ∼2000 cm−1 above that of the long-lived (25 ns) phosphorescence. In Os2, the 1MLCT−3MLCT intersystem crossing is faster than that in Os1, and no emission from triplet states is observed other than the lowest one. These observations are attributed to a higher density of states or a smaller energy spacing between them compared with Os1. They highlight the importance of the energetics on the rate of intersystem crossing.

UR - http://hdl.handle.net/10447/82427

M3 - Article

VL - 117

SP - 15958

EP - 15966

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

ER -