Donor fluorescence decay in the presence of forward and reverse excitationenergy transport in two-component disordered systems

A time-resolved study of forward and reverse excitation energy transport in a disordered two-component system of Na-fluorescein (donor) and rhodamine 6G (acceptor) in glycerol-ethanol solution is reported. The experimental re sults are compared with those of the hopping model (HM), accounting for the effect of reverse energy transfer. Quantitative agreement between the expe riment and the theory is found for critical parameters close to those obtai ned from independent spectral measurements, Simultaneously, disagreement be tween experimental data and no-reverse-transport HM theory was found for th is system. (C) 2000 Elsevier Science B.V. All rights reserved.