Exciton level structure and dynamics in tubular porphyrin aggregates

Yan Wan, Anna Stradomska, Sarah Fong, Zhi Guo, Richard D Schaller, Gary P. Wiederrecht, Jasper Knoester, Libai Huang

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We present an account of the optical properties of the Frenkel excitons in self-assembled porphyrin tubular aggregates that represent an analog to natural photosynthetic antennae. Using a combination of ultrafast optical spectroscopy and stochastic exciton modeling, we address both linear and nonlinear exciton absorption, relaxation pathways, and the role of disorder. The static disorder-dominated absorption and fluorescence line widths show little temperature dependence for the lowest excitons (Q band), which we successfully simulate using a model of exciton scattering on acoustic phonons in the host matrix. Temperature-dependent transient absorption of and fluorescence from the excitons in the tubular aggregates are marked by nonexponential decays with time scales ranging from a few picoseconds to a few nanoseconds, reflecting complex relaxation mechanisms. Combined experimental and theoretical investigations indicate that nonradiative pathways induced by traps and defects dominate the relaxation of excitons in the tubular aggregates. We model the pump-probe spectra and ascribe the excited-state absorption to transitions from one-exciton states to a manifold of mixed one- and two-exciton states. Our results demonstrate that while the delocalized Frenkel excitons (over 208 (1036) molecules for the optically dominant excitons in the Q (B) band) resulting from strong intermolecular coupling in these aggregates could potentially facilitate efficient energy transfer, fast relaxation due to defects and disorder probably present a major limitation for exciton transport over large distances.

Original languageEnglish
Pages (from-to)24854-24865
Number of pages12
JournalJournal of Physical Chemistry C
Volume118
Issue number43
DOIs
Publication statusPublished - Oct 30 2014

Fingerprint

Porphyrins
porphyrins
Excitons
excitons
disorders
LDS 751
Fluorescence
fluorescence
Defects
defects
Phonons
Electron transitions
Excited states
Linewidth
Energy transfer
phonons
antennas
Optical properties
Acoustics
energy transfer

ASJC Scopus subject areas

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

Cite this

Wan, Y., Stradomska, A., Fong, S., Guo, Z., Schaller, R. D., Wiederrecht, G. P., ... Huang, L. (2014). Exciton level structure and dynamics in tubular porphyrin aggregates. Journal of Physical Chemistry C, 118(43), 24854-24865. https://doi.org/10.1021/jp507435a

Exciton level structure and dynamics in tubular porphyrin aggregates. / Wan, Yan; Stradomska, Anna; Fong, Sarah; Guo, Zhi; Schaller, Richard D; Wiederrecht, Gary P.; Knoester, Jasper; Huang, Libai.

In: Journal of Physical Chemistry C, Vol. 118, No. 43, 30.10.2014, p. 24854-24865.

Research output: Contribution to journalArticle

Wan, Y, Stradomska, A, Fong, S, Guo, Z, Schaller, RD, Wiederrecht, GP, Knoester, J & Huang, L 2014, 'Exciton level structure and dynamics in tubular porphyrin aggregates', Journal of Physical Chemistry C, vol. 118, no. 43, pp. 24854-24865. https://doi.org/10.1021/jp507435a
Wan, Yan ; Stradomska, Anna ; Fong, Sarah ; Guo, Zhi ; Schaller, Richard D ; Wiederrecht, Gary P. ; Knoester, Jasper ; Huang, Libai. / Exciton level structure and dynamics in tubular porphyrin aggregates. In: Journal of Physical Chemistry C. 2014 ; Vol. 118, No. 43. pp. 24854-24865.
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