ENERGY MIGRATION PHENOMENA IN J-AGGREGATES .1. FLUORESCENCE LIFETIME MEASUREMENTS AND HOLE-BURNING EXPERIMENTS ON J-AGGREGATES OF A BENZIMIDOCARBOCYANINE DYE
M. Lindrum et al., ENERGY MIGRATION PHENOMENA IN J-AGGREGATES .1. FLUORESCENCE LIFETIME MEASUREMENTS AND HOLE-BURNING EXPERIMENTS ON J-AGGREGATES OF A BENZIMIDOCARBOCYANINE DYE, Chemical physics, 178(1-3), 1993, pp. 423-432
The photophysics of the J-aggregates of the cyanine dye 5,5',6,6'-tetr
achloro-1,1'-diethyl-3,3'-bis (4-sulfobutyl)-benzimidazolocarbocyanine
(TDBC) has been investigated with fluorescence lifetime measurements
and hole-burning experiments. The temperature dependence of the fluore
scence lifetime has been measured between 4 and 300 K with different s
olvent mixtures and different cooling procedures. At very low temperat
ures, the lifetime is nearly constant under different conditions. Betw
een 50 and 300 K the lifetime depends on solvent mixture and cooling p
rocedure indicating that the microscopic environment of the J-aggregat
e determines the fluorescence decay. At room temperature the fluoresce
nce lifetime depends linearly on the reciprocal viscosity as would be
expected for a diffusion controlled deactivation process under the Sto
kes-Einstein approximation. From the data, a hydrodynamic volume of 5
X 10(-28) m(3) can be derived. In contrast to the behavior of pseudois
ocyanine (PIC) aggregates, it has been impossible to burn holes in the
J-band of TDBC under the given experimental conditions. We conclude t
hat this discrepancy is due to the different aggregate structure of bo
th dyes. In the monomer band of TDBC in ethanol/methanol glass, howeve
r, holes can be burnt with prolonged irradiation.