Effect of Graphene Oxide Size and Structure on Synthesis and Optoelectronic Properties of Hybrid Graphene Oxide-Poly(3-hexylthiophene) Nanocomposites

Conjugated polymer-layered filler nanocomposites have received extensive interest as multifunctional materials in various futuristic applications. In this study, the effect of graphene oxide (GO) particle size on the synthesis, optical, and electrochemical properties of in situ prepared graphene oxide (GO)-poly(3-hexylthiophene) (P3HT) nanocomposites have been studied. The intercalation of GO with P3HT is inferred from shifting and broadening of the characteristic D-and G-bands of GO in Raman spectra and also the vibrational frequencies in FTIR. This interaction is further confirmed from increase of the optical band gap and the ellipsometry data. The UV-visible absorption maximum (lambda(max)) of P3HT decreases from 438 to 418 nm in the nanocomposite owing to ionic interactions between GO and the polymer causing a decrease of the polymer conjugation length. Compared to the homopolymer, the emission maximum of the composite is broadened and enhanced in intensity with 10 wt% GO but emission quenching is observed with GO nanoparticles. The evidence of polymer intercalation was also deduced from the determination of the basal spacing and unit cell dimensions of GO, using X-ray diffraction data. Morphological studies using field emission scanning electron microscopy suggest that the crystalline rod-like structures observed in the homopolymer have changed to more amorphous, flaky, and porous structures. The cyclic voltammetry studies show an increase in current with increasing GO content in the porous nanocomposites. (C) 2015 Society of Plastics Engineers