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...

Extensive environmental pollution caused by worldwide industrialization and population growth has led to a water shortage. This problem lowers the quality of human life and wastes a large amount of money worldwide each year due to the related consequences. One main solution for this challenge is water purification. State-of-the-art water purification necessitates the implementation of novel materials and technologies that are cost and energy efficient. In this regard, graphene nanomaterials, with their unique physicochemical properties, are an optimum choice. These materials offer extraordinarily high surface area, mechanical durability, atomic thickness, nanosized pores and reactivity toward polar and non-polar water pollutants. These characteristics impart high selectivity and water permeability, and thus provide excellent water purification efficiency. This review introduces the potential of graphene membranes for water desalination. Although literature reviews have mostly concerned graphene's capability for the adsorption and photocatalysis of water pollutants, updated knowledge related to its sieving properties is quite limited. NPG Asia Materials (2017) 9, e427; doi:10.1038/am.2017.135; published online 25 August 2017 INTRODUCTION Currently,~1.2 billion people around the world are suffering from a shortage of water and its adverse consequences on health, food and energy. 1,2 On one hand, population growth, increased industrialization and greater energy needs and, on the other hand, loss of snowmelt, shrinkage of glaciers and so on will worsen this situation in upcoming years. As estimated by the world water council, the number of affected people will rise to 3.9 billion in the coming decades. 2,3 One of the most promising approaches to alleviate the water shortage, desalination can increase the water supply beyond what is available from the hydrological cycle. 4 Seawater desalination indeed provides an infinite, steady supply of high-quality water that does not harm natural freshwater ecosystems.Seawater comprises a vast supply of water (97.5% of all water on the planet). Thus, the growth of the installation of seawater desalination facilities in the past decade to circumvent water shortage problems in water-stressed countries has progressed quickly. In 2016, the global water production by desalination was estimated to be 38 billion cubic meter per year, that is, two times higher than that in 2008. 5 So far, seawater desalination has been mainly performed via multistage flash distillation and reverse osmosis (RO). 6 Mostly in the arid Persian Gulf countries, desalination plants perform based on heating and then condensing seawater. This kind of desalination plant consumes large amounts of thermal and electric energy, thus emitting greenhouse gases extensively. 7 In addition to this non-economical and non-ecofriendly version of desalination plants, the main type of desalination plants constructed in the past two decades, as well as future planned ones, are based on RO technology (Figure 1). 8

Nanocomposites combine favorable features of the constituents on the nanoscale to obtain new functionalities. The present paper is concerned with the preparation of polymer‐based nanocomposites consisting of metal nanoparticles in a polymer matrix and the resulting functional properties. Emphasis is placed on vapor phase deposition which inter alia allows the incorporation of alloy clusters with well defined composition and tailored filling factor profiles. Examples discussed here include optical composites with tuned particle surface plasmon resonances for plasmonic applications, magnetic high frequency materials with cut‐off frequencies well above 1 GHz, sensors that are based on the dramatic change in the electronic properties near the percolation threshold, and antibacterial coatings which benefit from the large effective surface of nanoparticles and the increased chemical potential which both strongly enhance ion release.

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.

Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface _lasmon). These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on) perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented.

There is continued interest in finding quicker and simpler ways to fabricate nanowires, even though research groups have been investigating possibilities for the past decade. There are two reasons for this interest: first, nanowires have unusual properties-for example, they show quantum-mechanical confinement effects, they have a very high surface-to-volume ratio, enabling them to be used as sensors, and they have the ability to connect to individual molecules. Second, no simple method has yet been found to fabricate nanowires over large areas in arbitrary material combinations. Here we describe an approach to the generation of well-defined nanowire network structures on almost any solid material, up to macroscopic sample sizes. We form the nanowires within cracks in a thin film. Such cracks have a number of properties that make them attractive as templates for nanowire formation: they are straight, scalable down to nanometre size, and can be aligned (by using microstructure to give crack alignment via strain). We demonstrate the production of nanowires with diameter <16 nm, both singly and as networks; we have also produced aligned patterns of nanowires, and nanowires with individual contacts.

Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency) and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc., nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

Metamaterials and plasmonics as a new pioneering field in photonics joins the features of photonics and electronics by coupling photons to conduction electrons of a metal as surface plasmons (SP). This concept haven been implemented for variety of application including negative index of refraction, magnetism at visible frequencies, cloacking devices amongst others. In the present work, we used plasmonic hybrid material in order to design and fabricate a broad-band perfect plasmonic metamaterial absorber in a stack of metal and Copper-PTFE (Polytetrafluoroethylene) nanocomposite showing average absorbance of 97.5% in whole visible frequencies. Our experimental results showed that the absorption peak of the stacks can be tuned upon varying the thickness and type of the spacer layer due to the sensitivity of plasmon resonance to its environment. To the best of our knowledge this is the first report of plasmonic metamaterial absorber based on copper with absorption around 100% in entire visible and NIR.