Efficient and tunable absorption is essential for a variety of applications, such as the design of controlled emissivity surfaces for thermophotovoltaic devices1; tailoring of the infrared spectrum for controlled thermal dissipation2; and detector elements for imaging3. Metamaterials based on metallic elements are particularly efficient as absorbing media, because both the electrical and the magnetic properties of a metamaterial can be tuned by structured design4. To date, metamaterial absorbers in the infrared or visible range have been fabricated using lithographically patterned metallic structures2,5–9, making them inherently difficult to produce over large areas and hence reducing their applicability. We demonstrate here an extraordinarily simple method to create a metamaterial absorber by randomly adsorbing chemically synthesized silver nanocubes onto a nanoscale thick polymer spacer layer on a gold film –making no effort to control the spatial arrangement of the cubes on the film– and show that the film-coupled nanocubes provide a reflectance spectrum that can be tailored by varying the geometry. Each nanocube is the optical analog of the well-known grounded patch antenna, with a nearly identical local field structure that is modified by the plasmonic response of the metal dielectric function, and with an anomalously large absorption efficiency that can be partly attributed to an interferometric effect10. The absorptivity of large surface areas can be controlled using this method, at scales out of reach of lithographic approaches like e-beam lithography otherwise required to manipulate matter at the nanometer scale.

A novel mesoporous‐nanotube hybrid composite, namely mesoporous tin dioxide (SnO2) overlaying on the surface of multiwalled carbon nanotubes (MWCNTs), was prepared by a simple method that included in situ growth of mesoporous SnO2 on the surface of MWCNTs through hydrothermal method utilizing Cetyltrimethylammonium bromide (CTAB) as structure‐directing agents. Nitrogen adsorption–desorption, X‐ray diffraction and transmission electron microscopy analysis techniques were used to characterize the samples. It was observed that a thin layer tetragonal SnO2 with a disordered porous was embedded on the surface of MWCNTs, which resulted in the formation of a novel mesoporous‐nanotube hybrid composite. On the base of TEM analysis of products from controlled experiment, a possible mechanism was proposed to explain the formation of the mesoporous‐nanotube structure. The electrochemical properties of the samples as anode materials for lithium batteries were studied by cyclic voltammograms and Galvanostatic method. Results showed that the mesoporous‐tube hybrid composites displayed higher capacity and better cycle performance in comparison with the mesoporous tin dioxide. It was concluded that such a large improvement of electrochemical performance within the hybrid composites may in general be related to mesoporous‐tube structure that possess properties such as one‐dimensional hollow structure, high‐strength with flexibility, excellent electric conductivity and large surface area.

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One-dimensional (1-D) TiO2-B nanowires have been synthesized via a facile solvothermal route. The morphology and crystalline structures of the nanowires were characterized by using powder X-ray diffraction, low/high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller methods. It is important with the calcination treatment at 350 degrees C to maintain 1-D morphologies of the material in the form of single-crystalline TiO2-B nanowires. In addition, a simple method was used to study the photogenerated charge transfer and photoelectrochemical properties of the TiO2-B nanowires in comparison with commercial TiO2 P25 nanoparticles based on the experimental data from the electric field-effected photocurrent action spectrum and Mott-Schottky measurements. It was revealed that TiO2-B nanostructures played an important role in the photoelectrochemical processes. The synthetic TiO2-B nanowire electrode exhibited unique electronic properties, e.g., favorable charge-transfer ability, negative-shifted appearing flat-band potential, existence of abundant surface states or oxygen vacancies, and high-level dopant density. Moreover, the obtained TiO2-B nanowires were found to display excellent humidity sensing abilities as functional materials in the humidity sensor application. With relative humidity increased from 5% to 95%, about one and half orders of magnitude change in resistance was observed in the TiO2-B nanowire-based surface-type humidity sensors.