Single light emitters in electrospun polymer nanofibers: Effect of local confinement on radiative decay

The fabrication of light emitting polymer nanofibers by electrospinning of polymer solutions containing either fluorescent organic dye molecules or luminescent semiconductor nanoparticles (quantum dots) is presented. The fluorescence spectra and lifetime of the embedded emitters, down to the level of single molecules were investigated. While the average fluorescence lifetime of single molecules embedded in poly(methyl methacrylate) fibers appears independent of the fiber diameter, the single molecule approach reveals a significant broadening of the fluorescence lifetime distribution for fibers with diameters below the wavelength of light.