Gold nanoparticle hybridized rubrene nanofibers made by electrospinning: Enhancement of optical and structural properties

We prepared gold nanoparticle (Au NP) hybridized organic rubrene nanofibers (NFs) using a convenient electrospinning method. Au NPs of size 2-3 nm were incorporated throughout the light emitting rubrene NFs, which was confirmed by high resolution transmission electron microscopy. Au NP hybridized rubrene NFs showed a distinct nanoporous surface, compared to the smooth surface of rubrene NFs. Nanoscale confocal spectroscopy was performed on a single NF level and the results showed that the photoluminescence (PL) of the hybrid NFs made with 15 wt% Au NP mixture solution was 2.5 times higher than the PL of the rubrene NFs. And the optical extinction (scattering and absorption) of hybrid NFs increased monotonically with increasing Au NP concentrations. These enhanced optical properties of hybrid NFs were attributed to localized surface plasmon resonance of the embedded Au NPs. Structural modification from the monoclinic phase to the orthorhombic phase of the rubrene structure was obtained by XRD analysis indicating a better ordering along the rubrene ab plane of the hybrid NFs.