Electrical conductivity of oxidized-graphenic nanoplatelets obtained from bamboo: effect of the oxygen content

Abstract

Large-scale production of graphene and reduced-graphene oxide (rGO) requires low-cost and ecofriendly synthesis methods. We employed a new, simple, cost-effective pyrolytic method to synthetize oxidized-graphenic nanoplatelets (OGNP) using bamboo pyroligneous acid (BPA) as source. Thorough analyses via high-resolution transmission electron microscopy and electron energy-loss spectroscopy provides a complete structural and chemical description at the local scale of these samples. In particular, we found that at the highest carbonization temperature the OGNP-BPA are mainly in sp 2 bonding configuration (sp 2 fraction of 87%). To determine the electrical properties of single nanoplatelets, these were contacted by Pt nanowires deposited through focused-ion-beam-induced deposition techniques.Increased conductivity by two orders of magnitude is observed as oxygen content decreases from 17 to 5%, reaching a value of 2.3x10 3 S/m at the lowest oxygen content. Temperature-dependent conductivity reveals a semiconductor transport behavior, described by the Mott three-dimensional variable range hopping mechanism. From the localization length, we estimate a band-gap value of 0.2(2) eV for an oxygen content of 5%. This investigation demonstrates the great potential of the OGNP-BPA for technological applications, given that their structural and electrical behavior is similar to the highlyreduced rGO sheets obtained by more sophisticated conventional synthesis methods.

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

“…The complete method to determine the carbon sp 2 ratio has been detailed previously. 15,16 To minimize carbon contamination and irradiation beam damages, (S)TEM experiments were performed at liquid nitrogen temperature.…”

Advanced spectroscopic analyses on a:C-H materials: Revisiting the EELS characterization and its coupling with multi-wavelength Raman spectroscopy

“…S1 in the Supplementary Data). This has been tested on oxidized-graphenic nanoplatelets sample which contain 12 % of oxygen [80]. In this case, the error on the determination of the R ratio was estimated to be equal to 1.6 %.…”

Graphene oxide–carbon nanotube hybrid assemblies: cooperatively strengthened OH⋯OC hydrogen bonds and the removal of chemisorbed water

“…The key is the presence of oxygen functional groups (OFGs) located on GO’s basal plane and edges, essentially of the epoxy/hydroxyl and carbonyl/carboxyl types, respectively. 15 – 19 They facilitate the hydration/solvation of the GO sheets and impart hydrophilicity. However, when assembled into a stacked layer structure, water remains trapped between the assembled GO sheets.…”