Synthesis of CuO Nanorods, Reduction of CuO into Cu Nanorods, and Diffuse Reflectance Measurements of CuO and Cu Nanomaterials in the Near Infrared Region
ABSTRACT CuO nanorods were synthesized by hydrothermal methods with three different chemical combinations: (i) copper nitrate, lactic acid, and sodium hydroxide; (ii) copper sulfate, sodium lactate, and sodium hydroxide; and (iii) copper nitrate and sodium hydroxide. Physical parameters, concentration, temperature, and aging time, greatly affected the size and morphology of the nanorods; CuO nanoparticles were also prepared. These nanorods and nanoparticles were reduced to metallic copper at elevated temperature by 4% H2 diluted in helium. The morphology of CuO nanomaterials (nanorods and nanoparticles) was preserved after reduction. These CuO and Cu nanorods and nanoparticles were characterized by XRD, SEM, TEM, SEM-EDS, and BET measurements. The CuO and Cu nanomaterials were employed for near-infrared (NIR) diffuse reflectance. Among these materials, CuO nanorods were to be found the best NIR diffuse reflectors, indicating potential application as NIR obscurants.
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ABSTRACT: Scattering efficiencies of Ag–Cu, Ag–Au, and Au–Cu alloy nanoparticles are studied based on Mie theory for their possible applications in solar cells. The effect of size (radius), surrounding medium, and alloy composition on the scattering efficiency at the localized surface plasmon resonance (LSPR) wavelengths has been reported. In the alloy nanoparticles of Ag1−x Cux , Au1−x Cux and Ag1−x Aux ; the scattering efficiency gets red-shifted with increase in x. Moreover, the scattering efficiency enhancement can be tuned and controlled with both the alloy composition and the surrounding medium refractive index. A linear relationship which is in good agreement to the experimental observations between the scattering efficiency and metal composition in the alloys are found. The effect of nanoparticle size and LSPR wavelength (scattering peak position) on the full width half maxima and scattering efficiency has also been studied. Comparison of Au–Ag, Au–Cu, and Ag–Cu alloy nanoparticles with 50-nm radii shows the optical response of Ag–Cu alloy nanoparticle with wide bandwidth in the visible region of the electromagnetic spectrum making them suitable for plasmonic solar cells. Further, the comparison of Ag–Cu alloy and core@shell nanoparticles of similar size and surrounding medium shows that Cu@Ag nanoparticle exhibits high scattering efficiency with nearly the same bandwidth.Plasmonics 07/2013; · 2.43 Impact Factor
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ABSTRACT: We report the nitrogen monoxide (NO) gas sensing properties of p-type CuO-nanorod-based gas sensors. We synthesized the p-type CuO nanorods with breadth of about 30 nm and length of about 330 nm by a hydrothermal method using an as-deposited CuO seed layer prepared on a substrate by the sputtering method. We fabricated polycrystalline CuO nanorod arrays at under the hydrothermal condition of 1:1 morality ratio between copper nitrate trihydrate  and hexamethylenetetramine (). Structural characterizations revealed that we prepared the pure CuO nanorod array of a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the gas sensing measurements that the p-type CuO nanorod gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as . We also found that these CuO nanorod gas sensors showed reversible and reliable electrical response to NO gas at a range of operating temperatures. These results would indicate some potential applications of the p-type semiconductor CuO nanorods as promising sensing materials for gas sensors, including various types of p-n junction gas sensors.Korean Journal of Materials Research 01/2014; 24(1).
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ABSTRACT: Nanoscale metal oxide materials have been attracting much attention because of their unique size- and dimensionality-dependent physical and chemical properties as well as promising applications as key components in micro/nanoscale devices. Cupric oxide (CuO) nanostructures are of particular interest because of their interesting properties and promising applications in batteries, supercapacitors, solar cells, gas sensors, bio sensors, nanofluid, catalysis, photodetectors, energetic materials, field emissions, superhydrophobic surfaces, and removal of arsenic and organic pollutants from waste water. This article presents a comprehensive review of recent synthetic methods along with associated synthesis mechanisms, characterization, fundamental properties, and promising applications of CuO nanostructures. The review begins with a description of the most common synthetic strategies, characterization, and associated synthesis mechanisms of CuO nanostructures. Then, it introduces the fundamental properties of CuO nanostructures, and the potential of these nanostructures as building blocks for future micro/nanoscale devices is discussed. Recent developments in the applications of various CuO nanostructures are also reviewed. Finally, several perspectives in terms of future research on CuO nanostructures are highlighted.Progress in Materials Science 03/2014; 60:208–337. · 23.19 Impact Factor