Enhanced emission efficiency in electrospun polyfluorene copolymer fibers

We report on the unique emission features of light-emitting fibers made of a prototype conjugated polymer, namely, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1'-3}-thiadiazole)] (F8BT), realized by electrospinning with diameters in the range of 500-1000 nm. The fibers display emission polarized along their axis, evidencing a favoured alignment of the polymer molecules. Emission efficiency and time resolved measurements reveal an enhancement of both the quantum efficiency and the radiative rate (up to 22.5%) of the fibers compared to spin-coated films, shedding more light on their potential as miniaturized photon sources in optoelectronic devices requiring high recombination rates.