of the original manuscript:Hedayati, M.K.; Javaherirahim, M.; Mozooni, B.; Abdelaziz, R.; Tavassolizadeh, A.; Chakravadhanula, V.S.K.; Zaporojtchenko, V.; Strunkus, T.; Faupel, F.; Elbahri, M.: Design of a Perfect Black Absorber at Visible Frequencies Using Plasmonic MetamaterialsIn: Advanced Materials (2011) Submitted to 2 ((During the course of the last decade, trends to achieve perfect absorbers increased tremendously due to the huge interest in development of the materials for harvesting solar energy. However up to date all of the applied methods (perforated metallic films, [1][2][3] grating structured systems [4][5][6][7] , and metamaterials [8][9][10][11][12][13][14] ) are costly and suffer from a lack of flexibility.Furthermore their absorbance is limited to a narrow spectral range which makes their application for a broad range of frequencies impossible.Here we demonstrate design, fabrication and characterization of a perfect plasmonic absorber in a stack of metal and nanocomposite showing almost 100% absorbance spanning a broad range of frequencies from ultraviolet to the near infrared. The fabrication technique of our metamaterial is pretty simple, cost effective and compatible with current industrial methods of MEMS which make our proposed system an outstanding candidate for high efficiency absorber materials.Thick metallic film are known as an excellent mirror but when they are structured, the reflectance fades away because the light gets absorbed by the excitation of the conduction electrons by electromagnetic waves which is generally known as plasmon resonance.[1] This concept has been used in the last few decades to realize highly absorbing systems in diverse areas of the electromagnetic spectrum but these works were either successful only for a very narrow range of frequencies [7,[14][15][16] or the absorbance was distant from that of blackbody materials [11] .Not only the metallic film supports plasmon resonances but also the metallic nanoparticles show high absorption due to its localized particle plasmon resonance (Mie resonance) [17][18] Indeed, the resonance of these particles embedded in different matrices has been extensively studied within the last decade and it is well known that the resonance bandwidth depends on the size, shape, density and distribution of the nanoparticles. [17][18] Indeed, a highly dense nanocomposite gives rise to a very broad-band absorption due to the excitation of the localized plasmon resonance of the nanoparticles by visible light. [19] In contrast to the Submitted to 3 expectation for the absorption behavior of a metal/polymer nanocomposite, we have recently shown that nanocomposites with low filling factor in a proximity to a thin metallic film can even enhance the optical transmission of the system due to the plasmonic coupling of the film and the nanoparticles which mainly result in a reflection/scattering reduction of the system by dipole/image interaction. [20] However, rising the distance between the metallic film and the nanoparticles by adding a space...

Here we report for the first time the development of a Mg rechargeable battery using a graphene-sulfur nanocomposite as the cathode, a Mg-carbon composite as the anode and a non-nucleophilic Mg based complex in tetraglyme solvent as the electrolyte. The graphene-sulfur nanocomposites are prepared through a new pathway by the combination of thermal and chemical precipitation methods. The Mg/S cell delivers a higher reversible capacity (448 mA h g(-1)), a longer cyclability (236 mA h g(-1) at the end of the 50(th) cycle) and a better rate capability than previously described cells. The dissolution of Mg polysulfides to the anode side was studied by X-ray photoelectron spectroscopy. The use of a graphene-sulfur composite cathode electrode, with the properties of a high surface area, a porous morphology, a very good electronic conductivity and the presence of oxygen functional groups, along with a non-nucleophilic Mg electrolyte gives an improved battery performance.

Multicomponent rare earth oxide (REO) nanocrystalline powders containing up to seven equiatomic rare earth elements were successfully synthesized in a single-phase CaF 2-type (Fm-3 m) structure. The addition of more than six elements resulted in the formation of a secondary phase. Annealing at 1000°C for 1 h led to the formation of a single-phase (Ia-3) even in the 7-component system. In the absence of cerium (Ce 4+), secondary phases were observed irrespective of the number of cations or the extent of thermal treatment indicating that cerium cations played a crucial role in stabilizing the multicomponent REOs into a phase pure structure. IMPACT STATEMENT Multicomponent equiatomic rare earth oxides pioneer a new group of materials that crystallize into a single-phase structure with the dominant role of a single element instead of entropy.

In the search for novel battery systems with high energy density and low cost, fluoride ion batteries have recently emerged as a further option to store electricity with very high volumetric energy densities. Among metal fluorides, CuF 2 is an intriguing candidate for cathode materials due to its high specific capacity and high theoretical conversion potential. Here, the reversibility of CuF 2 as a cathode material in the fluoride ion battery system employing a high F − conducting tysonite-type La 0.9 Ba 0.1 F 2.9 as an electrolyte and a metallic La as an anode is investigated. For the first time, the reversible conversion mechanism of CuF 2 with the corresponding variation in fluorine content is reported on the basis of X-ray photoelectron spectroscopy measurements and cathode/electrolyte interfacial studies by transmission electron microscopy. Investigation of the anode/electrolyte interface reveals structural variation upon cycling with the formation of intermediate layers consisting of i) hexagonal LaF 3 and monoclinic La 2 O 3 phases in the pristine interface;ii) two main phases of distorted orthorhombic LaF 3 and monoclinic La 2 O 3 after discharging; and iii) a tetragonal lanthanum oxyfluoride (LaOF) phase after charging. The fading mechanism of the cell capacity upon cycling can be explained by Cu diffusion into the electrolyte and side reactions due to the formation of the LaOF compound.

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Green nanotechnology focuses on the development of new and sustainable methods of creating nanoparticles, their localized assembly and integration into useful systems and devices in a cost-effective, simple and eco-friendly manner. Here we present our experimental findings on the use of the Leidenfrost drop as an overheated and charged green chemical reactor. Employing a droplet of aqueous solution on hot substrates, this method is capable of fabricating nanoparticles, creating nanoscale coatings on complex objects and designing porous metal in suspension and foam form, all in a levitated Leidenfrost drop. As examples of the potential applications of the Leidenfrost drop, fabrication of nanoporous black gold as a plasmonic wideband superabsorber, and synthesis of superhydrophilic and thermal resistive metal–polymer hybrid foams are demonstrated. We believe that the presented nanofabrication method may be a promising strategy towards the sustainable production of functional nanomaterials.

This work highlights a strategy for the one-step synthesis of FeAu nanoparticles by the pulsed laser ablation of alloy targets in the presence of different solvents. This method allows particle generation without the use of additional chemicals; hence, solvent-metal interactions could be studied without cross effects from organic surface ligands. A detailed analysis of generated particles via transmission electron microscopy in combination with EDX elemental mapping could conclusively verify that the nature of the used solvent governs the internal phase structure of the formed nanoparticles. In the presence of acetone or methyl methacrylate, a gold shell covering a non-oxidized iron core was formed, whereas in aqueous media, an Au core with an Fe3O4 shell was generated. This core-shell morphology was the predominant species found in >90% of the examined nanoparticles. These findings indicate that fundamental chemical interactions between the nanoparticle surface and the solvent significantly contribute to phase segregation and elemental distribution in FeAu nanoparticles. A consecutive analysis of resulting Fe@Au core-shell nanoparticles revealed outstanding oxidation resistance and fair magnetic and optical properties. In particular, the combination of these features with high stability magnetism and plasmonics may create new opportunities for this hybrid material in imaging applications.

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