Rapid synthesis and decoration of reduced graphene oxide with gold nanoparticles by thermostable peptides for memory device and photothermal applications

Abstract

This article presents novel, rapid, and environmentally benign synthesis method for one-step reduction and decoration of graphene oxide with gold nanoparticles (NAuNPs) by using thermostable antimicrobial nisin peptides to form a gold-nanoparticles-reduced graphene oxide (NAu-rGO) nanocomposite. The formed composite material was characterized by UV/Vis spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM). HR-TEM analysis revealed the formation of spherical AuNPs of 5–30 nm in size on reduced graphene oxide (rGO) nanosheets. A non-volatile-memory device was prepared based on a solution-processed ZnO thin-film transistor fabricated by inserting the NAu-rGO nanocomposite in the gate dielectric stack as a charge trapping medium. The transfer characteristic of the ZnO thin-film transistor memory device showed large clockwise hysteresis behaviour because of charge carrier trapping in the NAu-rGO nanocomposite. Under positive and negative bias conditions, clear positive and negative threshold voltage shifts occurred, which were attributed to charge carrier trapping and de-trapping in the ZnO/NAu-rGO/SiO2 structure. Also, the photothermal effect of the NAu-rGO nanocomposites on MCF7 breast cancer cells caused inhibition of ~80% cells after irradiation with infrared light (0.5 W cm−2) for 5 min.

Reduced graphene oxide–coated anode gas diffusion layer for performance enhancement of proton‐exchange membrane fuel cell

“…Peaks at 283, 284.6, 286, and 288 eV, which were attributable to sp 2 (CC), sp 3 (CH), CO (hydroxyl, epoxide, ether, etc. ), and CO (carboxylic) bonds, respectively, could be seen . In the case of the RGO samples, the intensity of the sp 2 peak was higher, while those of the CO and CO peaks were lower than the corresponding peaks in the GO samples, thus confirming the reduction of GO.…”

“…), and C¼O (carboxylic) bonds, respectively, could be seen. [29][30][31] In the case of the RGO samples, the intensity of the sp 2 peak was higher, while those of the C-O and C¼O peaks were lower than the corresponding peaks in the GO samples, thus confirming the reduction of GO. By XPS and FTIR analysis, RGO was thus found to have residual oxygencontaining functional groups (C-O and C¼O) that can improve the hydrophilic nature of GDL.…”

Surface Functionalization of Green‐synthesized Reduced Graphene Oxide with PPIX Enhances Photosensitization of Cancer Cells

“…Reaction was then cooled by pouring into ice (~140 mL) with 30 % H 2 O 2 (3 mL). The mixture was filtered and centrifuged at 1360 g for 4 h. After removing the supernatant, the pellet was thoroughly washed in succession with 30% HCl, ethanol (39) and water (29) for each wash, and mixture was finally vacuum-dried overnight at room temperature.…”

Extracellular Synthesis and Characterization of Gold Nanoparticles Using Mycobacterium sp. BRS2A-AR2 Isolated from the Aerial Roots of the Ghanaian Mangrove Plant, Rhizophora racemosa

“…Gold nanoparticles with different shapes and sizes produced by diverse microorganisms perform numerous functions which are associated with many applications in the field of medicine, for example, diagnosis and therapy in cancer treatment, as potent antiangiogenic and antiarthritic agents and antimalarials. For instance, nanocomposites of Ag-graphene, Au-graphene or Au-SnO 2 have been developed for electrochemically active biofilms (EABs) and help in the bio-reduction of gold nanoparticles without the need to use capping or surfactants [11]. These nanocomposites have various applications including their use as sensors, photoelectrodes, optoelectronic devices, photocatalysis, photovoltaic, ultracapacitors and photovoltaics.…”