Journal of Physical Chemistry A, Vol.121, No.38, 7183-7190, 2017
Macroscopic Wires from Fluorophore-Quencher Dyads with Long-Lived Blue Emission
We report the formation of macroscopic wires up to centimeters in length from a series of structurally flexible, covalently tethered small-molecular fluorophore-quencher dyads (FQDs, average MW = 425 Da), comprised of carbazole, melatonin, and cyanobenzoate moieties. These FQDs are nonemissive in organic solutions but become moderately to highly luminescent (Phi(F) = 0.037-0.39) upon formation of wires with emission maxima in the blue region (446-483 nm). The blue photoluminescence (PL) is ascribed to a combination of singlet charge transfer, localized triplet state, and possibly delayed fluorescence emissions with intrinsic luminescence lifetimes ranging from 0.228 to 21333 mu s, based on luminescence, transient absorption measurements, X-ray diffraction, and calculations.