Near-field spectroscopy of water-soluble and water-insoluble porphyrin J-aggregates

Tetsuhiko Nagahara, Kohei Imura, Hiromi Okamoto

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Mesoscopic properties of J-aggregates of water-soluble [tetrakis(4- sulfonatophenyl)porphyrin] and water-insoluble [tetrakis(4-methoxyphenyl) porphyrin and tetraphenylporphyrin] tetraphenylporphyrin derivatives in thin films have been investigated by scanning near-field optical microscopy. From surface topography, the sample films were found to be composed of planar J-aggregate microcrystallines. The transmittance spectra of the water-insoluble samples are site specific, while those of the water-soluble samples are not. This observation might reflect the spatial inhomogeneity of the thin films in mesoscopic scales and is related to the broad J-bands of water-insoluble samples. Excited state lifetimes, obtained from time-resolved, pump-probe measurements in small domains, were in the 30-70 ps range for 4-methoxy substituted and in the 40-100 ps range for unsubstituted tetraphenylporphyrin, which are of the same order as the reported far-field results for 4-sulfonated compound in water.

Original languageEnglish
JournalScanning
Volume26
Issue number5 SUPPL.
Publication statusPublished - 2004
Externally publishedYes

Fingerprint

Porphyrins
porphyrins
near fields
Spectroscopy
water
spectroscopy
Water
Near field scanning optical microscopy
Thin films
Surface topography
thin films
Excited states
far fields
transmittance
topography
inhomogeneity
Pumps
pumps
microscopy
Derivatives

Keywords

  • J-aggregates
  • Scanning near-field optical microscopy
  • Time-resolved spectroscopy

ASJC Scopus subject areas

  • Instrumentation

Cite this

Near-field spectroscopy of water-soluble and water-insoluble porphyrin J-aggregates. / Nagahara, Tetsuhiko; Imura, Kohei; Okamoto, Hiromi.

In: Scanning, Vol. 26, No. 5 SUPPL., 2004.

Research output: Contribution to journalArticle

Nagahara, Tetsuhiko ; Imura, Kohei ; Okamoto, Hiromi. / Near-field spectroscopy of water-soluble and water-insoluble porphyrin J-aggregates. In: Scanning. 2004 ; Vol. 26, No. 5 SUPPL.
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