Preparation of Ag+/TiO2 Composite Coating Film for Preservation of Nanfeng Citrus

Using tetrabutyl titanate as the precursor, silver nitrate as the load agent, silver-doped titanium dioxide coating film was prepared by sol-gel method. Three agent samples were characterized by X-ray diffraction （XRD） analysis to investigate the crystal structure, which confirmed a synergistic antibacterial effect. The antibacterial and preservative effects of silver-doped titanium dioxide coating film on Nanfeng citrus were investigated preliminarily. Nutritional indicators of ripe Nanfeng citrus before and after preservation were detected to investigate the preservative properties of silver-doped titanium dioxide coating film and compare the effects of different components of composite coating film. The results showed that Ag＋/TiO2 composite coating film exhibited high antibacterial and preservative effects on Nanfeng citrus under visible light illumination condition.

Investigation of Negative Refraction Phenomenon for Au Nanowires Array Tuning with Index of Filling Material

Negative refraction performance of Au nanowires arrays-based metamaterials was explored by means of finite difference and time domain (FDTD) algorithm for the purpose of providing flexible design freedom of the negative index metamaterials (NIMs) working in visible regime from nanofabrication point of view. Tuning performance of the nanowires for negative refraction was analyzed by use of varying refractive index of filling materials among the metallic nanowires. Computational numerical simulation and analyses were carried out. The performance of negative refraction was compared by optimization of the structures. By optimizing the nanowires radius, E-field intensity was calculated in the case that the refractive index of filling material is changeable. The calculated refraction angles illustrate a relationship between the refraction angle and the index of filling material. Our computational results demonstrate that effective value of the negative refractive index strongly depends on the refractive index of the filling material when other parameters are fixed.

Facile sensitizing of PbSe film for near-infrared photodetector by microwave plasma processing

High quality PbSe film was first fabricated by a thermal evaporation method, and then the effect of plasma sensitization on the PbSe film was systemically investigated. Typical detectivity and significant photosensitivity are achieved in the PbSe-based photodetector, reaching maximum values of 7.6 × 10^(9)cm·Hz^(1/2)/W and 1.723 A/W, respectively. Compared with thermal annealing, plasma sensitization makes the sensitization easier and significantly improves the performance.

Optimization of Duty Ratio of Metallic Grating Arrays for Infrared Photodetectors

Influence of duty ratio of metallic gratings applied in quantum well infrared photodetector (QWIP) with detection ranging from 3 &#956m to 5 &#956m was studied in this paper. The influence on longer enhanced wavelength working at infrared waveband was investigated. A relationship between the duty ratio and the enhanced peak intensity is given. Some results can be applied to optimize the enhanced efficiency of the metallic gratings.

Germanium nanopyramid arrays showing near-100% absorption in the visible regime

Solar energy is regarded as one of the most plentiful sources of renewable energy. An extraordinary light-harvesting property of a germanium periodic nanopyramid array is reported in this Letter. Both our theoretical and experimental results demonstrate that the nanopyramid array can achieve perfect broadband absorption from 500- to 800-nm wavelength. Especially in the visible regime, the experimentally measured absorption can even reach 100%. Further analyses reveal that the intrinsic antireflection effect and slow-light waveguide mode play an important role in the ultra-high absorption, which is helpful for the research and development of photovoltaic devices.