Plasmon effect on simultaneous singlet-singlet and triplet-singlet energy transfer

Abstract

The influence of plasmonic effect of Ag nanoparticles (NPs) on singlet-singlet (S–S) and triplet-singlet (T–S) energy transfer in the same donor–acceptor pair of organic molecules was studied. It was established that a 7-fold increase in the fluorescence and phosphorescence intensity of the energy donor (Rose bengal) and a 4-fold increase in the fluorescence intensity of the acceptor (polymethine dye) are observed on silver island films. The changes are associated with an increase in the emission rate of dye molecules, as evidenced by a decrease in the lifetime of their luminescence in the presence of Ag NPs. An increase in the efficiency of both types of energy transfer was recorded in the plasmon field of Ag NPs. The plasmon effect has almost the same influence on both S–S and T–S energy transfer. Estimation of the energy transfer rates using of the model of electric dipole interaction showed a good correlation between the experimental and calculated data for the S–S energy transfer.