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The effects of annealing on the physical and optical properties of CuS/CuInGaSe (CuS/CIGS) core/shell nanowire arrays were studied. CuS nanowire arrays and CIGS shell layers were prepared by a solid-gas reaction and electrodeposition, respectively. The structure and light absorption properties of CuS/CIGS core/shell nanowire arrays were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and diffuse reflectance spectroscopy. The melting point of CuS nanowire arrays increased after the electrodeposition of CIGS. The crystallinity of the CIGS shell layer increased with increasing annealing temperature from 350 to 650 °C, and most of the amorphous area of the CIGS shell layer becomes twin crystals after thermal annealing. The CuS/CIGS core/shell structure collapsed when the annealing temperature increased to 800 °C. The light absorption properties of the CuS/CIGS core/shell structure were enhanced after thermal annealing, and the band gap corresponding to CIGS was also obtained. This study indicates that the annealing temperature should be controlled between 350 and 800 °C to convert this CuS/CIGS core/shell structure to a CuInGa(Se, S) (CIGSS) one-dimensional nanostructure. This research demonstrates the potential for preparing CIGSS one-dimensional nanostructures by thermal annealing. [ABSTRACT FROM AUTHOR]

Epoxy samples were surface fluorinated in a laboratory vessel using a F/N gas mixture to suppress surface charge accumulation. Attenuated total reflection infrared analyses indicate that the fluorination led to substantial variations in chemical composition and structure of the sample surface layer. Measurement results of surface properties indicate that surface conductivity and wettability or polarity were dramatically increased by the fluorination. A very likely decrease in charge trap depth and the adsorbed water on the surface in air are responsible for the high surface conductivity. As a result, charge cannot accumulate on the fluorinated surface even at room temperature, rapidly transporting along the surface. Surface charging current measurements further show a much larger steady state current flowing along the fluorinated surface, suggesting much lower dynamic surface potential or charge density during charging, compared with those for the original surface. [ABSTRACT FROM AUTHOR]

In this work, we report the CaCu3Ti4O12 ceramics synthesized through a sintering process using organo-metallic compound method. The acetate reagents of Ca(CH3COO)2·H2O and Cu(CH3COO)2·H2O were used as the precursor, and TiO(acac)2 as source of titanium. The TG-DTA curves show that the reaction process of the mixture is simple and quick caused by synergistic effect of precursors. The XRD results indicate that the pure CaCu3Ti4O12 phase appear at 800 °C and the high temperature and longer holding time are apt to form the uniform CaCu3Ti4O12 crystal and well crystallinity. The SEM images show that the grain sizes and the grain uniformity of the CaCu3Ti4O12 ceramics can be influenced significantly by temperature and holding time. The dielectric constant and the dielectric loss show good frequency stability. [ABSTRACT FROM AUTHOR]