Large Area Films of Alternating Graphene–Carbon Nanotube Layers Processed in Water

Abstract

We report the preparation of hybrid paperlike films consisting of alternating layers of graphene (or graphene oxide) and different types of multiwalled carbon nanotubes (N-doped MWNTs, B-doped MWNTs, and pristine MWNTs). We used an efficient self-assembly method in which nanotubes were functionalized with cationic polyelectrolytes in order to make them dispersible in water, and subsequently these suspensions were mixed with graphene oxide (GO) suspensions, and the films were formed by casting/evaporation processes. The electronic properties of these films (as produced and thermally reduced) were characterized, and we found electrical resistivities as low as 3 × 10(-4) Ω cm. Furthermore, we observed that these films could be used as electron field emission sources with extraordinary efficiencies; threshold electric field of ca. 0.55 V/μm, β factor as high as of 15.19 × 10(3), and operating currents up to 220 μA. These values are significantly enhanced when compared to previous reports in the literature for other carbon nanostructured filmlike materials. We believe these hybrid foils could find other applications as scaffolds for tissue regeneration, thermal and conducting papers, and laminate composites with epoxy resins.

Evaluating the thermal damage resistance of graphene/carbon nanotube hybrid composite coatings

“…Second, a peak centered around 240°C. This peak is significant in the low CNT % samples, which indicates it may be due to removal of labile oxygen groups in GO39. A third peak centered around 480°C and 595°C are due to the presence of MWCNTs in the sample.…”

“…It is clear that specimens with higher rGO percentage were more reflecting, particularly at increasing wavelengths. This could be attributed to the presence of carboxy, epoxy, alkoxy carbons and perhaps trace metallic impurities that are present in rGO (prepared by modified Hummer's method) even after thermal reduction3239. The presence of optimum amount of CNTs and complete thermal reduction of GO in the composite is therefore crucial for applications that demand uniform optical absorbance for a broad range of wavelength (UV to far IR).…”

Densely packed graphene nanomesh-carbon nanotube hybrid film for ultra-high volumetric performance supercapacitors

“…However, ion transport at the electrochemical interfaces is critical for effective energy storage in supercapacitors [26]. Recent advances in designing "spacers" in-between sheets, such as carbon nanotubes, [27][28][29] water, [30] liquid electrolyte, [15] open up new ways to address this challenge. For example, the packing density of film can be adjusted by controlling "spacers" content trapped in the film, and its high volumetric capacitance is up to 255 F cm À 3 at 0.1 A g À 1 in aqueous electrolyte [15].…”

Optical Kerr effect exhibited by carbon nanotubes and carbon/metal nanohybrid materials

“…(8)(9)(10)(11)(12)(13)(14)(15) were computed to fit the experimental transmitted probe irradiance data. The extracted nonlinear refractive index was calculated to be n 2 ¼ À2.1 Â 10 À 15 m 2 /W for the Pt/MWCNTs and n 2 ¼ À1.1 Â 10 À 15 m 2 /W for the SWCNTs/ MWCNTs.…”

“…Furthermore, it has been claimed that engineering the geometrical configuration of carbon nanostructured distributions can strongly modify their physical effects [13,14]. Concerning to nanostructured thin films, a simple way that could be considered for the addition of optical resonant interactions in a sample is the contribution of different materials assembling nanocomposites [15]. An evident advantage of the participation of metallic nanoparticles with CNTs is an automatic increment in the area/volume relation when they are arranged as a thin film sample.…”