The structural, optical, thermal, and electrical properties of synthesized PEO/GO thin films

We report a successful preparation of graphene oxide (GO) from a graphite powder using a modified low-temperature Hummer's method. Different concentrations of the prepared GO are then incorporated into the PEO polymer matrix to yield PEO/GO thin films using the casting method. The measured thickness of as-prepared nanocomposite thin films is 500 nm. The measured X-ray diffraction (XRD) patterns reveal the formation of a new diffraction peak at 14.68 degrees associated with the crystallographic GO (001) plane. This peak confirms the uniform substitution of GO into the PEO matrix. Key optical parameters of PEO/GO thin films are studied by measuring their transmittance and reflectance spectra. Furthermore, Tauc's model is employed to investigate the behavior of the optical bandgap energy (Eg). Two well-established classical models are implemented to investigate and interpret the key dispersion parameters. To identify the major vibrational bands associated with different bonding modes of the PEO/GO nanocomposite, Fourier transform infrared radiation (FTIR) profiles are measured. The small shift in the FTIR peaks provides substantial evidence of the charge transport between the PEO matrix and GO. Furthermore, a small variation of the intensity of the vibrational band associated with the C-O-C stretching as well as differential scanning calorimetry (DSC) results reveals a decrease in the crystallinity degree of the PEO/GO thin films. The conductivity mapping shows an excellent distribution of GO in the PEO matrix. Interestingly, the electrical conductivity of PEO/GO nanocomposite considerably increases upon the incorporation of 8 wt% of GO. The increase could be interpreted in terms of bridging the gap between the localized states of the nanocomposite. Several design and power requirements of future consumer optoelectronic devices and transparent energy storage devices require cost-effective integrated design of effective electrode materials based on polymer/graphene nanocomposites.