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Metallodielectric materials with plasmonic resonances at optical and infrared wavelengths are attracting increasing interest, due to their potential novel applications in the fields of photonics, plasmonics and photovoltaics. However, simple and fast fabrication methods for three‐dimensional bulk plasmonic nanocomposites that offer control over the size, shape and chemical composition of the plasmonic elements have been missing. Here, such a manufacturing method and examples of experimental realizations of volumetric isotropic nanocomposites doped with plasmonic nanoparticles that exhibit resonances at visible and infrared wavelengths are presented. This method is based on doping a low‐melting dielectric material with plasmonic nanoparticles, using a directional glass‐solidification process. Transmission‐spectroscopy experiments confirm a homogenous distribution of the nanoparticles, isotropy of the material and resonant behavior. The phenomenon of localized surface plasmon resonance is also observed visually. This approach may enable rapid and cost‐efficient manufacturing of bulk nanoplasmonic composites with single or multiple resonances at various wavelength ranges. These composites could be isotropic or anisotropic, and potentially co‐doped with other chemical agents, in order to enhance different optical processes.

Due to the development of novel manufacturing technologies and the increasing availability of nano‐/micromaterials, plasmonics has become an emerging field in photonics research. Although the fabrication of metallic elements has already been widely demonstrated, the development of 3D plasmonic materials is progressing slowly. This paper reports the development of a self‐organized, 3D nanoplasmonic eutectic composite that exhibits localized surface plasmon resonance at 595 nm. This eutectic composite is produced by directional solidification with the micro‐pulling‐down method and consists of a 3D, multiscale network of silver, nanometer‐thick, micron‐long sheets, and triangular cross‐section microprecipitates embedded in a crystalline bismuth oxide matrix. Annealing at 600 °C further refined the structure and introduced metallic nanoparticles that exhibited plasmonic resonance in the optical region of the spectrum. This is the first demonstration of plasmonic behavior in a eutectic‐based composite, which is engineered specifically for this purpose using a self‐organization mechanism.

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Conventional metal wires suffer from a significant degradation or complete failure in their electrical performance, when subjected to harsh oxidizing environments, however wires constructed from Carbon Nanotubes (CNTs) have been found to actually improve in their electrical performance when subjected to these environments. These opposing reactions may provide new and interesting applications for CNT wires. Yet, before attempting to move to any real-world harsh environment applications, for the CNT wires, it is essential that this area of their operation be thoroughly examined. To investigate this, CNT wires were treated with multiple combinations of the strongest acids and halogens. The wires were then subjected to conductivity measurements, current carrying capacity tests, as well as Raman, microscopy and thermogravimetric analysis to enable the identification of both the limits of oxidative conductivity boosting and the onset of physical damage to the wires. These experiments have led to two main conclusions. Firstly, that CNT wires may operate effectively in harsh oxidizing environments where metal wires would easily fail and secondly, that the highest conductivity increase of the CNT wires can be achieved through a process of annealing, acetone and HCl purification followed by either H2O2 and HClO4 or Br2 treatment.