Optical Property Characterization of Novel Graphene‐X (X=Ag, Au and Cu) Nanoparticle Hybrids

Abstract

The present investigation reports new results on optical properties of graphene-metal nanocomposites. These composites were prepared by a solution-based chemical approach. Graphene has been prepared by thermal reduction of graphene oxide (GO) at 90°C by hydrazine hydrate in an ammoniacal medium. This ammoniacal solution acts as a solvent as well as a basic medium where agglomeration of graphene can be prevented. This graphene solution has further been used for functionalization with Ag, Au, and Cu nanoparticles (NPs). The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Vis spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to reveal the nature and type of interaction of metal nanoparticles with graphene. The results indicate distinct shift of graphene bands both in Raman and UV-Vis spectroscopies due to the presence of the metal nanoparticles. Raman spectroscopic analysis indicates blue shift of D and G bands in Raman spectra of graphene due to the presence of metal nanoparticles except for the G band of Cu-G, which undergoes red shift, reflecting the charge transfer interaction between graphene sheets and metal nanoparticles. UV-Vis spectroscopic analysis also indicates blue shift of graphene absorption peak in the hybrids. The plasmon peak position undergoes blue shift in Ag-G, whereas red shift is observed in Au-G and Cu-G.

One-Pot Green Synthesis of Highly Reduced Graphene Oxide Decorated with Silver Nanoparticles

“…The C=C peak of Ag-rGO-AA shifts to a longer wavelength (271 nm) than GO (228 nm) and Ag-rGO (230 nm). This red shifting shows the rapid occurrence of electronic conjugation after the promotion of GO reduction by ascorbic acid (Dinh et al 2014;Sahu et al 2013). This can also be seen by the disappearance of the shoulder of C=O peak at 300 nm in Ag-rGO-AA sample (Golsheikh et al 2014).…”

“…The red shifting of AgNPs peak to 424 nm in Ag-rGO-AA as compared to Ag-rGO can be related to the increase of AgNPs size (Paramelle et al 2014). (Golsheikh et al 2014) Chemical synthesis (Sahu et al 2013) Chemical synthesis (Liu et al 2015) Sonochemical and annealing (Dinh et al 2014 Table 1 shows the comparison of the UV-vis absorbance peaks in the presence of different reducing agent. Commonly, hydrazine is being used to reduce GO despite its toxicity.…”

“…Gao et al (2010b) concluded from their work that hydrazine can only reduce epoxy and hydroxyl groups located at the interior of an aromatic domain, which makes it a less effective reducing agent. Sahu et al (2013) reported the observation of absorption peak at 260 nm in GO sample reduced by hydrazine. Remarkably, 271 nm was obtained using ascorbic acid in this work.…”

“…Therefore, the effort to produce the AgNPs-rGO that can possess two important properties; excellent coating uniformity when is dispersed on the substrate; and highly reduction, becomes necessary. Recently, AgNPs-rGO composite is synthesized using the sonochemical and chemical approaches (Golsheikh et al 2014;Sahu et al 2013). Unfortunately, the reduction rate of the composite is still low.…”

Thermoplasmonics-assisted nanoheterostructured Au-decorated CuInS2 nanoparticles: Matching solar spectrum absorption and its application on selective distillation of non-polar solvent systems by thermal solar energy

“…To tackle and broaden absorption ranges of NPs, hybrid NPs such as Fe 3 O 4 /Au, [9] SiO 2 /Fe 2 O 3 -Au, [10] Au/TiO 2 , [11] Au/Pd, [12] SiO 2 /Au, [13][14][15][16] Graphene/Au, [17] Ag/Au, [18] SiO 2 /Ag [19] and VO 2 /Au [20] have been proposed, which provide advantages of equivalent light absorption by an increase of absorption cross-section compared with the counterpart materials NPs, thereby consuming less volume of metal NPs. In addition, superimposing functionalities such as magnetic and optical dual properties can be contributed from hybrid NPs for possible applications at bio-imaging, [9] thermal ablation of bacterium [9] and ambient oxygen-free dehydrogenation of aromatic alcohols by catalytic-thermal plasmonic effect [12].…”