Super-sensitization mechanism of T-Grain AgBrI emulsion sensitized by an anionic−cationic cyanine dye

The transient time-resolved fluorescence decay spectrum of J-aggregates of an anionic−cationic cyanine dye adsorbed on tabular AgBrI nanocrystals has been investigated using femtosecond fluorescence up-conversion technology. The kinetics of the super-sensitization of the anionic−cationic cyanine dye is discussed in detail. The J-aggregates of the anionic−cationic cyanine dye have two excited states. Thus, more electrons are transferred from the excited states of the anionic−cationic cyanine dye to the conduction band of T-grain AgBrI. It is shown that the cations and anions in the anionic−cationic cyanine dye give rise to reciprocal super-sensitization effects in the red and green regions respectively.