Remarkable thermal conductivity enhancement in Ag—decorated graphene nanocomposites based nanofluid by laser liquid solid interaction in ethylene glycol

We report on the synthesis and enhanced thermal conductivity of stable Ag-decorated 2-D graphene nanocomposite in ethylene glycol based nanofluid by laser liquid solid interaction. A surfactant free nanofluid of Ag nanoparticles anchored onto the 2-D graphene sheets were synthesized using a two-step laser liquid solid interaction approach. In order to understand a pulsed Nd:YAG laser at the fundamental frequency (λ = 1,064 nm) to ablate Ag and graphite composite target submerged in ethylene glycol (EG) to form AgNPs decorated 2-D GNs-EG based nanofluid. From a heat transfer point of view, it was observed that the thermal conductivity of this stable Ag-graphene/EG is significantly enhanced by a factor of about 32.3%; this is highest reported value for a graphene based nanofluid

Optical properties of biosynthesized nanoscaled Eu2O3 for red luminescence applications

This contribution reports on the optical properties of biosynthesised Eu2O3 nanoparticles bioengineered for the first time by a green and cost effective method using aqueous fruit extracts of Hyphaene thebaica as an effective chelating and capping agent. The morphological, structural, and optical properties of the samples annealed at 500°C were confirmed by using a high-resolution transmission electron microscope (HR-TEM), x-ray diffraction analysis (XRD), UV–Vis spectrocopy, and photoluminescence spectrometer. The XRD results confirmed the characteristic body-centered cubic (bcc) structure of Eu2O3 nanoparticles with an average size of 20 nm. HR-TEM revealed square type morphology with an average size of ∼6nm. Electron dispersion energy dispersive x-ray spectroscopy spectrum confirmed the elemental single phase nature of pure Eu2O3. Furthuremore, the Fourier transformed infrared spectroscopy revealed the intrinsic characteristic peaks of Eu−O bond stretching vibrations. UV–Vis reflectance proved that Eu2O3 absorbs in a wide range of the solar spectrum from the VUV–UV region with a bandgap of 5.1 eV. The luminescence properties of such cubic structures were characterized by an intense red emission centered at 614 nm. It was observed that the biosynthesized Eu2O3 nanoparticles exhibit an efficient red-luminescence and hence a potential material as red phosphor

Photoluminescence and dynamics of excitation relaxation in graphene oxide-porphyrin nanorods composite

International audienceGenerally, porphyrin nanostructured materials are known by playing many roles such as photoconductors, photovoltaics and capable of light induced charging. Also their combination with acceptors like graphene, the rising two dimension material, added exciting physical and chemical properties. In this work, Morphology, optical absorption and photoluminescence properties were investigated in order to elucidate the interaction between the few layered graphene oxide (FGO) and pophyrin nanorods. Reporting on the photoluminescence (PL) of both porphyrin nanorods and FGO/porphyrin nanorods composite, synthesized via a self-assembly method, we have experimentally demonstrated the generation of a new photoluminescence band giving rise to a white light. This luminescence was studied by the analysis of its origins and dynamics which show a huge change of exciton life time found to be longer after the interaction with graphene oxide (GO) sheets. (C) 2013 Elsevier B.V. All rights reserved

Synthesis and opto-structural characterization of reduced graphene oxide and meso-tetrakis(4-phenylsulfonic-acid) porphyrin composites

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Structural and photophysical studies of few layers of reduced graphene oxide functionalized with Sn(IV) tetrakis (4-pyridyl)porphyrin dichloride

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Optical properties and dynamics excitation relaxation in reduced graphene oxide functionalized with nanostructured porphyrins

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Graphene / TiO2 composites synthesized in one-step by laser pyrolysis for improved charge extraction in perovskite solar cells

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