Two-photon fluorescence spectroscopy of individually trapped pseudoisocyanine J-aggregates in aqueous solution

Yoshito Tanaka, Hiroyuki Voshikawa*, Hiroshi Masuhara

*Corresponding author for this work

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

We have investigated a pseudoisocyanine dye aqueous solution including nanometer-sized J-aggregates by combining optical trapping and two-photon fluorescence spectroscopy. By focusing an intense near-infrared laser into an 8 × 10-3 M solution, the intense fluorescence from J-aggregates for a few to tens of seconds is observed intermittently, indicating that individual J-aggregates are trapped in and diffuse out from a focal spot. The peak position and full width at half-maximum of the J-band are different from each other. By measuring 171 J-aggregates, it was found that J-aggregates can be classified largely into two groups. The existence of two kinds of groups of J-aggregates could be attributed to the difference in the nucleation process, which is affected by the substrate. J-aggregates possessing a J-band of a narrower bandwidth in a shorter wavelength region are trapped for a longer period of time, indicating that highly ordered J-aggregates are trapped for a longer period of time because of their high polarizability.

Original languageEnglish
Pages (from-to)17906-17911
Number of pages6
JournalJournal of Physical Chemistry B
Volume110
Issue number36
DOIs
StatePublished - 14 Sep 2006

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