Donor fluorescence decay in the presence of forward and reverse excitation energy 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 results are compared with those of the hopping model (HM), accounting for the effect of reverse energy transfer. Quantitative agreement between the experiment and the theory is found for critical parameters close to those obtained from independent spectral measurements. Simultaneously, disagreement between experimental data and no-reverse-transport HM theory was found for this system.