Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules

Neil A. Montgomery, Gordon J. Hedley, Arvydas Ruseckas, Jean-Christophe Denis, Stefan Schumacher, Alexander L. Kanibolotsky, Peter Skabara, Ian Galbraith, Graham A. Turnbull, Ifor D. W. Samuel

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Star-shaped molecules are of growing interest as organic optoelectronic materials. Here a detailed study of their photophysics using fluorescence depolarisation is reported. Fluorescence depolarisation dynamics are studied in branched oligofluorene-truxene molecules with a truxene core and well-defined three-fold symmetry, and are compared with linear fluorene oligomers. An initial anisotropy value of 0.4 is observed which shows a two-exponential decay with time constants of 500 fs and 3-8 ps in addition to a long-lived component. The femtosecond component is attributed to exciton localisation on one branch of the molecule and its amplitude reduces when the excitation is tuned to the low energy tail of the absorption spectrum. The picosecond component shows a weak dependence on the excitation wavelength and is similar to the calculated rate of the resonant energy transfer of the localised exciton between the branches. These assignments are supported by density-functional theory calculations which show a disorder-induced splitting of the two degenerate excited states. Exciton localisation is much slower than previously reported in other branched molecules which suggests that efficient light-harvesting systems can be designed using oligofluorenes and truxenes as building blocks. "

LanguageEnglish
Pages9176-9184
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number25
DOIs
Publication statusPublished - 2012

Fingerprint

Depolarization
depolarization
Stars
Fluorescence
stars
fluorescence
Molecules
excitons
molecules
excitation
oligomers
Oligomers
Excited states
Optoelectronic devices
Energy transfer
time constant
Density functional theory
Absorption spectra
Anisotropy
energy transfer

Keywords

  • Star-shaped molecules
  • fluorescence depolarisation
  • oligofluorenes
  • truxenes

Cite this

Montgomery, N. A., Hedley, G. J., Ruseckas, A., Denis, J-C., Schumacher, S., Kanibolotsky, A. L., ... Samuel, I. D. W. (2012). Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules. Physical Chemistry Chemical Physics, 14(25), 9176-9184. https://doi.org/10.1039/c2cp24141b
Montgomery, Neil A. ; Hedley, Gordon J. ; Ruseckas, Arvydas ; Denis, Jean-Christophe ; Schumacher, Stefan ; Kanibolotsky, Alexander L. ; Skabara, Peter ; Galbraith, Ian ; Turnbull, Graham A. ; Samuel, Ifor D. W. / Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules. In: Physical Chemistry Chemical Physics. 2012 ; Vol. 14, No. 25. pp. 9176-9184.
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Montgomery, NA, Hedley, GJ, Ruseckas, A, Denis, J-C, Schumacher, S, Kanibolotsky, AL, Skabara, P, Galbraith, I, Turnbull, GA & Samuel, IDW 2012, 'Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules' Physical Chemistry Chemical Physics, vol. 14, no. 25, pp. 9176-9184. https://doi.org/10.1039/c2cp24141b

Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules. / Montgomery, Neil A.; Hedley, Gordon J.; Ruseckas, Arvydas; Denis, Jean-Christophe; Schumacher, Stefan; Kanibolotsky, Alexander L.; Skabara, Peter; Galbraith, Ian; Turnbull, Graham A.; Samuel, Ifor D. W.

In: Physical Chemistry Chemical Physics, Vol. 14, No. 25, 2012, p. 9176-9184.

Research output: Contribution to journalArticle

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T1 - Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules

AU - Montgomery, Neil A.

AU - Hedley, Gordon J.

AU - Ruseckas, Arvydas

AU - Denis, Jean-Christophe

AU - Schumacher, Stefan

AU - Kanibolotsky, Alexander L.

AU - Skabara, Peter

AU - Galbraith, Ian

AU - Turnbull, Graham A.

AU - Samuel, Ifor D. W.

PY - 2012

Y1 - 2012

N2 - Star-shaped molecules are of growing interest as organic optoelectronic materials. Here a detailed study of their photophysics using fluorescence depolarisation is reported. Fluorescence depolarisation dynamics are studied in branched oligofluorene-truxene molecules with a truxene core and well-defined three-fold symmetry, and are compared with linear fluorene oligomers. An initial anisotropy value of 0.4 is observed which shows a two-exponential decay with time constants of 500 fs and 3-8 ps in addition to a long-lived component. The femtosecond component is attributed to exciton localisation on one branch of the molecule and its amplitude reduces when the excitation is tuned to the low energy tail of the absorption spectrum. The picosecond component shows a weak dependence on the excitation wavelength and is similar to the calculated rate of the resonant energy transfer of the localised exciton between the branches. These assignments are supported by density-functional theory calculations which show a disorder-induced splitting of the two degenerate excited states. Exciton localisation is much slower than previously reported in other branched molecules which suggests that efficient light-harvesting systems can be designed using oligofluorenes and truxenes as building blocks. "

AB - Star-shaped molecules are of growing interest as organic optoelectronic materials. Here a detailed study of their photophysics using fluorescence depolarisation is reported. Fluorescence depolarisation dynamics are studied in branched oligofluorene-truxene molecules with a truxene core and well-defined three-fold symmetry, and are compared with linear fluorene oligomers. An initial anisotropy value of 0.4 is observed which shows a two-exponential decay with time constants of 500 fs and 3-8 ps in addition to a long-lived component. The femtosecond component is attributed to exciton localisation on one branch of the molecule and its amplitude reduces when the excitation is tuned to the low energy tail of the absorption spectrum. The picosecond component shows a weak dependence on the excitation wavelength and is similar to the calculated rate of the resonant energy transfer of the localised exciton between the branches. These assignments are supported by density-functional theory calculations which show a disorder-induced splitting of the two degenerate excited states. Exciton localisation is much slower than previously reported in other branched molecules which suggests that efficient light-harvesting systems can be designed using oligofluorenes and truxenes as building blocks. "

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JO - Physical Chemistry Chemical Physics

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Montgomery NA, Hedley GJ, Ruseckas A, Denis J-C, Schumacher S, Kanibolotsky AL et al. Dynamics of fluorescence depolarisation in star-shaped oligofluorene-truxene molecules. Physical Chemistry Chemical Physics. 2012;14(25):9176-9184. https://doi.org/10.1039/c2cp24141b