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Title: Can H-aggregates serve as light-harvesting antennae? Triplet-triplet energy transfer between excited aggregates and monomer thionine in aerosol-OT solutions

Abstract

The cationic dye thionine undergoes slow dissolution in aerosol-OT (AOT) containing solutions of heptane and toluene. By controlling the ratio of [dye]/[AOT], it is possible to obtain varying amounts of monomer, dimer, and higher order aggregates (trimer) in dilute dye solutions. The thionine aggregates exhibit characteristic absorption maxima at 565 and 530 nm for the dimer and trimer forms, respectively. The singlet excited states of these dye aggregates are short-lived ({tau} = 40--63 ps) as they undergo efficient intersystem crossing to generate the triplet excited states. Triplet energy transfer from the excited dye aggregates to monomeric thionine molecules was observed upon excitation with a 532 nm laser pulse. Pulse radiolysis experiments, in which the excited triplet states were generated indirectly, also confirm the finding that the triplet energy cascades down from excited trimer to dimer to monomeric dye. These studies demonstrate the possibility of using H-type dye aggregates as antenna molecules to harvest light energy whereby the aggregate molecules absorb light in different spectral regions and subsequently transfer energy to the monomeric dye.

Authors:
;  [1]
  1. Notre Dame, IN (United States). Radiation Lab.
Publication Date:
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
315952
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 103; Journal Issue: 1; Other Information: PBD: 7 Jan 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ENERGY ABSORPTION; ENERGY TRANSFER; THIONINE; AEROSOLS; VISIBLE RADIATION; MONOMERS; AGGLOMERATION; EXCITED STATES; LASER RADIATION

Citation Formats

Das, S., and Kamat, P.V. Can H-aggregates serve as light-harvesting antennae? Triplet-triplet energy transfer between excited aggregates and monomer thionine in aerosol-OT solutions. United States: N. p., 1999. Web. doi:10.1021/jp983816j.
Das, S., & Kamat, P.V. Can H-aggregates serve as light-harvesting antennae? Triplet-triplet energy transfer between excited aggregates and monomer thionine in aerosol-OT solutions. United States. doi:10.1021/jp983816j.
Das, S., and Kamat, P.V. Thu . "Can H-aggregates serve as light-harvesting antennae? Triplet-triplet energy transfer between excited aggregates and monomer thionine in aerosol-OT solutions". United States. doi:10.1021/jp983816j.
@article{osti_315952,
title = {Can H-aggregates serve as light-harvesting antennae? Triplet-triplet energy transfer between excited aggregates and monomer thionine in aerosol-OT solutions},
author = {Das, S. and Kamat, P.V.},
abstractNote = {The cationic dye thionine undergoes slow dissolution in aerosol-OT (AOT) containing solutions of heptane and toluene. By controlling the ratio of [dye]/[AOT], it is possible to obtain varying amounts of monomer, dimer, and higher order aggregates (trimer) in dilute dye solutions. The thionine aggregates exhibit characteristic absorption maxima at 565 and 530 nm for the dimer and trimer forms, respectively. The singlet excited states of these dye aggregates are short-lived ({tau} = 40--63 ps) as they undergo efficient intersystem crossing to generate the triplet excited states. Triplet energy transfer from the excited dye aggregates to monomeric thionine molecules was observed upon excitation with a 532 nm laser pulse. Pulse radiolysis experiments, in which the excited triplet states were generated indirectly, also confirm the finding that the triplet energy cascades down from excited trimer to dimer to monomeric dye. These studies demonstrate the possibility of using H-type dye aggregates as antenna molecules to harvest light energy whereby the aggregate molecules absorb light in different spectral regions and subsequently transfer energy to the monomeric dye.},
doi = {10.1021/jp983816j},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
number = 1,
volume = 103,
place = {United States},
year = {1999},
month = {1}
}