树枝状与球状PbS纳米结构的组装合成及其形成机理研究

以醋酸铅为铅源,硫代乙酰胺为硫源,在表面活性剂SDS单独作用和表面活性剂SDS和CTAB共同作用下可选择性地组装合成出颗粒以相同晶面粘连组装成的单晶树枝状PbS纳米结构和颗粒以不相同晶面粘连组装成的多晶球状PbS纳米结构,而且提高反应物浓度能起到调节树枝状和球状PbS纳米结构尺寸的作用.对树枝状和球状PbS纳米结构的形成机理进行了初探,发现SDS单独作用时其烷基链起到的软模板作用有利于PbS小颗粒组装成树枝状的PbS纳米结构.当反应溶液中再加入适量的CTAB时,它在溶液中形成微胶束起到了软模板作用,迫使颗粒粘连组装成球状PbS纳米结构,有效地限制树枝状结构的生长.     

碳纳米管

概述了碳纳米材料的发展及它们的性能和应用,同时介绍了一些比较成熟的制备纳米材料的技术。在此基础上分析了碳纳米管的形成过程和碳纳米管的微观结构,以及碳纳米管制备工艺对微观结构的影响。     

Grain effect in electronic properties of silicon epitaxial nanostructures

The electronic properties of grained nanocrystalline silicon (1 1 1) films were theoretically studied within the self-consistent semiempirical LCAO method. Grains in the films were found to provide a direct band gap and their interaction results in the gap reduction with respect to the one in the isolated grain. The gap value varied from 1.55 to 3.04 eV depending on the film thickness as well as on the lateral size of the grains. Grained layer stacking inside the film induces a considerable increase of the gap as compared to the unstacked film of the same effective thickness. New simple approach based on the effective mass theory (EMT) has been developed and successfully applied to simulate the electronic properties of nanocrystalline films accounting for confinement effects and interaction between the grains. It consistently reproduces main features of the properties of the grained films derived from LCAO calculations.     

花状纳米氧化锌颗粒的制备及其光学性能研究

以硬脂酸锌和过氧化氢为原料，采用油相法一步合成出一种特殊的氧化锌花状纳米结构。利用透射电镜、高分辨电镜、X射线衍射等对其形貌和结构的分析表明：花状氧化锌纳米颗粒结构为六方晶相，大小约为30nm。吸收光谱和荧光光谱测量显示该纳米结构有显著的近带边紫光发射特性，对应的缺陷发光强度较弱，表明这一纳米结构有较好的光学特性，因此在生物荧光标记方面有着潜在的应用价值。     

Bioinspired study of energy and electron transfer in photovoltaic system

ABSTRACT

This study focuses on understanding the fundamentals of energy transfer and electron transport in photovoltaic devices with uniquely designed nanostructures by analysing energy transfer in purple photosynthetic bacteria using dye-sensitised solar cell systems. Förster resonance energy transfer between the xanthene dye (donor of energy) and a new polymethine dye (acceptor of energy) was studied in dye-sensitised solar cells, which leads to a doubling of energy conversion efficiency in comparison to the cell with only the polymethine dye. The electron transport in the two different nanostructures of zinc oxide (nanorods and nanosheets) was investigated by spectroscopic methods (UV-vis spectrometer, time-resolved photoluminescence spectroscopy) and electrochemical potentiostat methods. The nanosheet structure of zinc oxide showed high short circuit current and long diffusion length. This fundamental study will lead to efficient artificial photosystem designs.     

Colloids of Holey Gd2O3 Nanosheets Converted from Exfoliated Gadolinium Hydroxide Layers

This paper proposes a confined solid‐state conversion approach using layered metal‐hydroxides for the production of a colloidal suspension of porous 2D crystalline metal oxide layers with superior electrochemical H₂O₂ sensing performance. This study investigates the conversion chemistry of delaminated layers of gadolinium hydroxide (LGdH), [Gd₂(OH)₅]⁺, encapsulated in a silica nanoshell that provides an antistacking and antisintering environment during the phase‐transition at high temperature. Thermal treatment of the LGdH layers within the protected environment results in a dimensionally confined phase‐transition into crystalline Gd₂O₃ nanosheets with an isomorphic 2D structure. Furthermore, annealing at higher temperatures leads to the evolution of in‐plane mesoporous structure on the Gd₂O₃ nanosheet. Based on insight acquired from in‐depth investigation, the evolution of in‐plane porosity proceeds through the in‐plane dominant silicate‐formation reaction at the interface with the surrounding silica shell. Their 2D‐anisotropic and mesoporous morphological features are preserved, producing a colloidal suspension of holey nanosheets that can be used to fabricate a thin and porous film through wet‐coating deposition. This study also demonstrates the superior electrochemical H₂O₂ sensing ability of the resultant porous Gd₂O₃ film, which represents a ≈1000‐ and 10‐fold enhancement of the detection limit and sensitivity, respectively, in comparison to previously reported Gd₂O₃ films.     

柱撑粘土高温形成纳米结构的研究

将聚羟基铝离子引入蒙脱石层间，制成柱撑粘土，将柱撑粘土在1100℃下煅烧，在煅烧过程中会形成纳米结构。其中莫来石的直径约为100～500nm，镁铝尖晶石直径小于100nm。将柱撑粘土加入到陶瓷基体材料中，在煅烧过程形成的纳米结构中可以起到颗粒弥散增强的作用。     

Structural analysis of anodic porous alumina used for resistive random access memory

Abstract

Anodic porous alumina with duplex layers exhibits a voltage-induced switching effect and is a promising candidate for resistive random access memory. The nanostructural analysis of porous alumina is important for understanding the switching effect. We investigated the difference between the two layers of an anodic porous alumina film using transmission electron microscopy and electron energy-loss spectroscopy. Diffraction patterns showed that both layers are amorphous, and the electron energy-loss spectroscopy indicated that the inner layer contains less oxygen than the outer layer. We speculate that the conduction paths are mostly located in the oxygen-depleted area.     

Fabrication of nanostructured pearlite steel wires using electropulsing

This work reports the refinement of pearlite structure into nanostructure using electropulsing. Nanostructured pearlitic steel wires possess nanoscale lamellae or nanoscale grain microstructures. Fabrication of nanostructures by severe plastic deformation and lamellar to grain transformation have been investigated. It is suggested that an aligned pearlite structure is preferred in severe plastic deformation. The lamellar to grain transformation is controlled by diffusion of carbon within cementite and also from cementite to ferrite phases. Carbon mobility is changed by mechanical, thermal and electrical states. The interface between nanoscale sub-grains in the ferrite phase has considerable carbon content. Numerical calculations and experimental observations demonstrated these mechanisms.     

纳米多孔无机材料的显微结构设计

综述了近年来在制备纳米多孔无机材料时对材料显微结构设计的一些主要思路，并结合近年来纳米多孔无机材料在能源、光电子、材料、化工等领域的实际应用，讨论了此类材料目前面临的问题和今后研究发展的方向。众多研究显示，充分发挥纳米尺寸孔的结构优势和无机材料本身优良的化学性能是此类材料开发的核心思路。对材料纳米结构的控制、梯度孔径的控制、表面修饰技术、制备工艺的优化可改善材料性能，拓展其应用领域；新型纳米多孔无机材料将朝着多种材料复合，多级结构并存的方向发展。     

脉冲电流处理后低碳钢中的局域纳米结构

用透射电镜观察经过高密度脉冲电流处理后的粗晶低碳钢，发现该材料中有纳米结构的γ-Fe生成。讨论了纳米结构的生成机制。脉冲电流作用时间短，加热速度快，改变相变势垒的效应和快速冷却的条件是生成纳米结构的原因，电流降低热力学形核势垒是一个不容忽视的因素。     

纳米结构的自组装高分子研究进展

评述了3种纳米结构自组装高分子，包括树枝状高分子、嵌段共聚物和缔合高分子。并且介绍了这3种高分子形成的几种纳米结构以及自组装的方式。     

ZnO基纳米电子材料研究进展

纳米ZnO的许多优异性能使其成为人们研究的热点并得到广泛应用.ZnO是一种同时具有半导体和压电双重特性的材料.运用不同的工艺,目前已生长出纳米线(棒)、纳米带、纳米环、四角形纳米结构、纳米笼、纳米螺旋等多种特殊形态的纳米ZnO.由这些许多独特的形态,可以看出纳米ZnO是纳米材料家族中可以生长出的结构最多样的成员之一.这些纳米结构在光电、传导、传感以及生化等不同领域有很多潜在的新颖的应用前景.     

分子自组装体系的影响因素及其在纳米材料中的应用

介绍了分子自组装体系的影响因素以及分子自组装技术在纳米材料制备方面的应用,并对聚合物自组装体系及研究进展作了综述.     

Designing Heterogeneous 1D Nanostructure Arrays Based on AAO Templates for Energy Applications

In order to fulfill the multiple requirements for energy production, storage, and utilization in the future, the conventional planar configuration of current energy conversion/storage devices has to be reformed, since technological evolution has promoted the efficiency of the corresponding devices to be close to the theoretical values. One promising strategy is to construct multifunctional 1D nanostructure arrays to replace their planar counterparts for device fabrication, ascribing to the significant superiorities of such 1D nanostructure arrays. In the last three decades, technologies based on anodic aluminium oxide (AAO) templates have turned out to be valuable meaning for the realization of 1D nanostructures and have attracted tremendous interest. In this review, recent progress in energy‐related devices equipped with heterogeneous 1D nanostructure arrays that fabricated through the assistance of AAO templates is highlighted. Particular emphasis is given on how to develop efficient devices via optimizing the componential and morphological parameters of the 1D nanostructure arrays. Finally, aspects relevant to the further improvement of device performance are discussed.     

纳米颗粒自组装合成氧化锆奇异纳米结构的研究

通过微乳液方法制备了Zr(OH)4前驱体,在添加KCl的条件下对其进行热处理,获得了ZrO2的奇异纳米结构,包括规则的六边形纳米颗粒、纳米晶须和纳米管.试验表明,氯离子在纳米颗粒自组装过程中起着重要作用.采用透射电镜(TEM)、选取电子衍射(SAED)和X射线衍射(XRD)对试样进行了分析表征.