Study on time-resolved fluorescence dynamics of cyanine dye sensitizing AgBr

The fluorescence spectra of three different dyes adsorbed on the tabular and cubic AgBr microcrystals are obtained by the picosecond time-resolved streak camera technique. The dependence of the ultrafast electron transferring from dye-aggregates to the conduction band of AgBr and the efficiency of spectral sensitization on different kinds of dyes with different concentrations is analyzed. Further more, the microcosmic mechanism of the sensitization process is discussed. It is found that the fluorescence decay curves are fitted very well by the double exponential function, consisting of a slow component and a fast one with large amplitude. We consider this fast one mainly attributable to the electron transfer from dye J-aggregates to the conduction band of AgBr. Supported by the National Natural Science Foundation of China (Grant No. 60478033), the Doctoral Foundation of Hebei Province of China (Grant No. B2003119), and the Science and Technology Project of Hebei Province of China (Grant No. 05215102)