TADF Dye-Loaded Nanoparticles for Fluorescence Live-Cell Imaging.

Thermally activated delayed fluorescence (TADF) molecules offer nowadays a powerful tool in the development of novel organic light emitting diodes due to their capability of harvesting energy from non-emissive triplet states without using heavy-metal complexes. TADF emitters have very small energy difference between the singlet and triplet excited states, which makes thermally activated reverse intersystem crossing from the triplet states back to the singlet manifold viable. This mechanism generates a long-lived delayed fluorescence component which can be explored in the sensing of oxygen concentration, local temperature, or used in time-gated optical cell-imaging, to suppress interference from autofluorescence and scattering.

Highly efficient singlet-singlet energy transfer in light-harvesting [60,70]fullerene-4-amino-1,8-naphthalimide dyads.

New C60 and C70 fullerene dyads formed with 4-amino-1,8-naphthalimide chromophores have been prepared by the Bingel cyclopropanation reaction. The resulting monoadducts were investigated with respect to their fluorescence properties (quantum yields and lifetimes) to unravel the role of the charge-transfer naphthalimide chromophore as a light-absorbing antenna and excited-singlet-state sensitizer of fullerenes. The underlying intramolecular singlet-singlet energy transfer (EnT) process was fully characterized and found to proceed quantitatively (Φ(EnT)≈1) for all dyads.