Graphene Oxide Thin Films: Synthesis and Optical Characterization

Abstract

The oxidized derivative of graphene named Graphene oxide (GO) are attractive materials as optoelectronic devices due to their optical response in the mid-infrared wavelength spectral range; however, very large-scaled synthesis methods and optical characterization are required. Here, GO thin films are fabricated on quartz by implementing simple two-step pyrolysis processes by using renewable bamboo as source material. The effect of carbonization temperature (T CA) on the compositional, vibrational, and optoelectronic properties of the system are investigated. It was found that as T CA increases, graphite conversion rises, oxygen coverage reduces from 17 % to 4 %, and the band-gap energy monotonically decreases from 0.30 to 0.11 eV. Theoretical predictions of the energy band-gap variations with the oxide coverage obtained via density functional theory (DFT) computational simulations agree well with the experimental results, providing evidence of oxygen-mediated charge-transport scattering. Interestingly, in the optical response, increased T CA results in a blue-shift of the absorption and the absorbance spectrum can be correlated with the large size distribution of the graphitic nano-crystals of the samples. These results suggest that graphene oxide-bamboo pyroligneous acid (GO) thin films exhibit optoelectronic response useful in developing photodetectors and emitter devices in the mid-infrared (MIR) spectral range.

Graphene Oxide: Comparisons between Experimental and Computational Simulation of HR-TEM Images

“…The GO samples were morphologically and structurally characterized by transmission electron microscopy (TEM) and high-resolution (HR)-TEM images, obtained by using the Tecnai F20 Super Twin TMP on a FEI microscope operating at 80 kV and equipped with a Cs image corrector and a Gatan Tridiem spectrometer; for more details, see [41][42][43].…”

“…A second pyrolysis step used the pyroligneous acid as a source material to obtain GO nanoplatelet samples at different carbonization temperatures (TCA = 673, 773, 873, and 973 K) during 1 h. Powders of GO nanoplatelets were obtained by mechanical grinding and subsequent sonication, filtering, and selection procedures, employing the Langmuir-Blodgett method. For more details on the synthesis method, please refer to [41][42][43].…”

“…The transport properties of GO can be influenced by the multilayered configuration [16] and presence of defects [17]. All these effects can be exploited in different fields [18] and applications from batteries [19][20][21][22], energy storage [23][24][25], electronics [26][27][28][29][30][31][32][33], catalysis [34], metal sorption [35], hydrogen storage [36], as well as to obtain graphene oxide monolayers [37][38][39][40][41][42][43][44], films, fibers, and membranes [45].…”

“…These methods are excellent for basic research. However, the double-thermal decomposition method in a pyrolysis system has proven to be a low-cost alternative and eco-friendly technique to synthesize stable graphene oxide multilayers, using bamboo waste products as source material at higher temperatures from 573 to 973 K; very different compared to traditional methods, as reported [41][42][43][44]. Higher temperatures promote elimination of organic compounds and oxygen functional groups, inducing formation of hydroxyl and epoxy bridges as multifunctional groups, leading to improvement in the crystal structure and positively impacting on the thermal, electrical, and magnetic transport [41][42][43][44][45][46][47][48][49][50].…”

Exploring Molecular and Electronic Property Predictions of Reduced Graphene Oxide Nanoflakes via Density Functional Theory

“…Due to its characteristics, GO is of interest in various fields such as biomedicine, physics, electronics, biotechnology, water treatment, and nanotechnology, among others. GO is defined as the carbon layers that are one atom thick, decorated with multifunctional oxides, the groups among which are hydroxyl, carbonyl, carboxyl, and epoxy; these groups give graphene an sp3 configuration, but it also contains aromatic rings; they also give it the property of dispersion in organic solvents and stability in water . Also, GO’s band gap energy and chemical potential can vary depending on the degree of oxidation and working temperature.…”