Preparation of graphene-polyaniline composites by simple chemical procedure and its improved field emission properties

Graphene-polyaniline composites have been synthesized using simple chemical procedure in two different ways (i) by mixing of the pre-synthesized graphene and polyaniline nanofibers and (ii) by in situ polymerization in presence of graphite oxide followed by further reduction. Detailed optical spectroscopic studies of the synthesized composites along with the pristine polyaniline nanofibers were performed by Fourier transformed infrared spectroscopy and UV-vis spectroscopy. The structural and morphological characterizations were performed by X-ray diffraction, transmission electron microscope measurements and field emission scanning electron microscope measurements, respectively while the chemical characters were studied by X-ray photoelectron spectroscopic measurement. The graphene-polyaniline composite retained the photoluminescence property of the as synthesized polyaniline nanofibers. The electron field emission property of the composite showed marked improvement compared to pristine polyaniline fibers with a turn-on field as low as 3.91 V/mu m at a current density of 1 mu A/cm(2). The field enhancement factor was found to be 7012 which is much higher for the case of a polymer based composite. (C) 2011 Elsevier Ltd. All rights reserved.