Fabrication and Optical Properties of Periodic Ag Nano‐Pore and Nano‐Particle Arrays with Controlled Shape and Size over Macroscopic Length Scales

A facile and economical route to preparation of highly ordered sliver pore or particle arrays with controlled pore‐shape and size extended over cm² areas is described. The substrates are prepared at planar and curved surfaces via sphere‐imprinted polymer (PDMS) templating using polystyrene spheres with diameters of 820, 600, or 430 nm. Nano‐pore arrays are created by sputtering 80 nm of Ag directly onto the templates and nano‐particle arrays are prepared by electrode‐less deposition of Ag from Tollen's reagent. The shape of the nano‐pore or particles in the array conformed to that of the imprint of the sphere on the template. Stretching the flexible template enable creation of cuboid shaped nano‐voids and nano‐particles following Ag deposition. Diffuse reflectance from the spherical Ag nano‐cavity arrays showed absorbance maxima at wavelengths comparable similar to the diameter of the templating sphere, whereas reflectance from the cuboid arrays, showed little correlation with the sphere diameter. The cuboid nano‐particle arrays showed the most intense visible absorption which is red‐shifted compared to the spherical arrays. White light diffraction from the arrays, observed by rotating 1 cm² substrates relative to a fixed light source, reflected exactly the symmetry axes of the periodic nano‐features in the arrays demonstrating the remarkable macroscopic order of the periodic structures. Raman spectra of 1‐benzenethiol adsorbed at the arrays indicated SERS enhancements from the substrates are attributed mainly to surface nano‐roughness with only moderate contributions from the periodically corrugated structures. Despite excitation at the major resonance dip in the reflectance spectrum, a weak, localized rim dipole mode is found to elicit a small increase in the SERS enhancement factor for the 430 nm diameter spherical arrays. FDTD studies of nano‐void arrays provided insights into v arious factors affecting the SERS experiment and confirmed the array's plasmonic spectra are dominated by propagating plasmon modes under microscope excitation/collection angles.     

值得关注的有机光伏电池材料

评述了近十年来有机光电池材料研究的最新进展，强调了材料复合对设计有机光伏电池的重要性，指出了有机半导体材料的分子聚集态结构与材料凝聚态结构的调控在改善器件性能上发挥的决定性作用，揭示了激发态过程与激发态性质的研究在提高光电转换效率上的意义，分析了有机光电池材料的发展前景。     

Are linear prebuckling paths and linear stability problems mutually conditional?

Stability problems are termed linear if the tangent stiffness used for determining loss of stability has a specific, simple form. The term “linear prebuckling paths” refers to the shape of the load–displacement diagrams before loss of stability. In this note, it will be shown that these two terms are not mutually conditional.     

Orientation control of epitaxial Ge thin films growth on SrTiO3 (100) by ultrahigh vacuum sputtering

We report the orientation control of crystalline Ge (111) and Ge (001) growth on SrTiO₃ (100) substrate by adjusting the temperature of substrate. It is found that the substrate temperature plays an important role for the formation of crystalline Ge with different surface orientations and interfacial chemical configuration during the sputtering process. At 500 °C, Ge (111) with good crystalline quality is formed, while Ge (001) is preferably grown on SrTiO₃ substrate at 650 °C. Our results show the possibility of manipulating the surface orientations during Ge growth on SrTiO₃ by controlling the substrate temperatures.     

阳极氧化铝的原子层淀积封孔研究

制备了多孔阳极氧化铝,利用原子层淀积技术对其封孔,借助场发射扫描电镜(SEM)分析了样品的表面及剖面形貌,对样品进行染色处理,利用酸性点滴试验测试样品抗腐蚀性能。结果表明:阳极氧化处理形成大孔径约为16 nm的多孔膜,多孔膜在循环50次的原子层淀积下能实现表面封孔而内部有空结构;经封孔后的样品抗染色及抗腐蚀能力增强。     

有机/聚合物图像传感材料的研究进展

总结了有机/聚合物图像传感器材料的主要特点,对几类典型的材料体系,如共轭聚合物/C60复合体系、共轭聚合物/无机半导体纳米微粒复合体系、酞菁类和生物材料进行了重点评述,讨论了给/受体的电子结构、光致电荷转移过程、复合材料的相分离行为对传感器光敏性的影响。指出了目前有机/聚合物图像传感材料研究中亟待解决的关键科学问题。     

Fluorescence near gold nanoparticles for DNA sensing

We investigated fluorescence quenching and enhancement near gold nanoparticles (GNP) of various sizes using fluorescently labeled hairpin DNA probes of different lengths. A closed hairpin caused intimate contact between the fluorophore and the gold, resulting in an efficient energy transfer (quenching). Upon hybridization with complementary DNA, the DNA probes were stretched yielding a strong increase in fluorescence signal. By carefully quantifying the amount of bound fluorescent probes and the GNP concentrations, we were able to determine the quenching and enhancement efficiencies. We also studied the size and distance dependence theoretically, using both FDTD simulations and the Gersten-Nitzan model and obtained a good agreement between experiments and theory. On the basis of experimental and theoretical studies, we report over 96.8% quenching efficiency for all particle sizes tested and a maximal signal increase of 1.23 after DNA hybridization. The described results also demonstrate the potential of gold nanoparticles for label free DNA sensing.     

三芳胺类空穴传输材料研究新进展

综述了广泛应用于有机光电器件的三芳胺类空穴传输材料的研究新进展,探讨了该类材料的分子设计思想,并对其分子结构与性能关系作了概述。     

四-(全氟苯基)-卟啉锌与四苯基卟啉锌的比较研究

用紫外-可见吸收光谱和循环伏安法对四-（全氟苯基）-卟啉锌和四苯基卟啉锌的电子结构进行了对比研究,发现外围氟取代可以有效提高卟啉锌的氧化电位而不改变其电子跃迁能隙。通过四-（全氟苯基）-卟啉锌和四苯基卟啉锌的吸收性状、透射电镜下的微观形态和X射线衍射图样的对比分析,发现外围氟取代使分子的排列方式、晶体生长模式和晶格类型都明显改变。     

大型工件平面度平行度垂直度误差计算与评定方法

提出了一种实用的大型工件平面度、平行度、垂直度误差的计算与评定方法。这种方法适用于各种不规则、不连续的测量表面。评定程序采用最小二乘和最小条件法，搜素速度快，评定结果精度高。