Non-coherent exciton migration in J-aggregates of the dye THIATS: exciton-exciton annihilation and fluorescence depolarization

Exciton-exciton annihilation (EEA) in J-aggregates of 3,3'-disulfopropyl-5, 5'-dichloro-9-ethylthiacarbocyanine in solution at room temperature and at 77 K was related to incoherent exciton migration within large aggregate dom ains. Inside a domain, the rate constant for EEA was estimated to be at lea st 1.5 times smaller than that of exciton decay. The experimental results w ere incompatible with one-dimensional incoherent exciton transport. The int ensity dependence of the fluorescence anisotropy decay was assigned to EEA. At 77 K and in the absence of EEA, the average angle of the transition dip ole changed less than 25 degrees during exciton migration over a domain. (C ) 1998 Elsevier Science B.V. All rights reserved.