Hole-transfer induced energy transfer in perylene diimide dyads with a donor-spacer-acceptor motif.

We investigate the photoinduced dynamics of perylene diimide dyads based on a donor-spacer-acceptor motif with polyyne spacers of varying length by pump-probe spectroscopy, time resolved fluorescence, chemical variation and quantum chemistry. While the dyads with pyridine based polyyne spacers undergo energy transfer with near-unity quantum efficiency, in the dyads with phenyl based polyyne spacers the energy transfer efficiency drops below 50%. This suggests the presence of a competing electron transfer process from the spacer to the energy donor as the excitation sink.

Förster resonant energy transfer in orthogonally arranged chromophores.

We investigate the ultrafast resonant energy transfer of a perylene bisimide dyad by pump-probe spectroscopy, chemical variation, and calculations. This dyad undergoes transfer with near-unit quantum efficiency, although the transition dipole moments of the donor and acceptor are in a perfectly orthogonal arrangement to each other in the equilibrium geometry. According to the point dipole approximation used in Förster theory, no energy transfer should occur.

Fluorescent silica nanoparticles by silylation.

Shining nanosil: Fluorescent trimethoxysilanes were prepared by the hydrosilylation of N-allyl perylene tetracarboxylic diimides and used for the covalent grafting of silica and silica nanoparticles (see picture). The fluorescent chromophores operate independently at the surface of these particles.