Low temperature synthesis of thiol‐functionalized CdTe nanoclusters with different tellurium contents

In recent years thiol‐functionalized cadmium telluride nanoparticles act as a core layers for obtaining high photovoltaic efficiency in conjugated polymer/inorganic nanocrystal solar cells and also provide easy tuning of quantum size effect by varying thiol groups and processing temperature. In this work, thiol functionalized CdTe nanoclusters were prepared for different tellurium concentrations at low temperature and its impact has been discussed. Structural parameters estimated by X‐ray diffraction revealed hexagonal phases at lower tellurium concentration and cubic phase at higher tellurium concentrations. Surface morphology of the samples analyzed by transmission electron microscopy, exhibited cluster type of morphology. Optical band gap energy estimated by diffused electron microscopy showed an increase with Te content and band edge emission has been observed in the photoluminescence spectra of CdTe nanoclusters around 620 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

紫外光辐照下以PAMAM树形分子为模板制备Ag纳米簇及光致发光性能研究

以G5.0-OH PAMAM树形分子为模板,用紫外光辐照法制备银纳米簇.用透射电子显微镜、紫外-可见吸收光谱和共振散射光谱等对所制备的银纳米簇进行了表征.结果表明:用紫外光辐照法可以制备尺寸分布均匀、稳定的银纳米簇;且辐照时间、PAMAM树形分子的浓度及Ag⁺/PAMAM树形分子的摩尔比都会对所制备的银纳米簇产生较大的影响.由于所制备的银纳米簇的粒径小于树形分子的流体力学半径,表明树形分子起到了“内模板”作用.同时研究了银纳米簇的尺寸对其光致发光性能的影响,发现通过调节银纳米簇的尺寸可实现其光致发光的可调性.     

Coherent Vibrational Dynamics of [Au25(SR)18]- Nanoclusters?

Coherent vibrational dynamics can be observed in atomically precise gold nanoclusters using femtosecond time-resolved pump-probe spectroscopy. It can not only reveal the coupling between electrons and vibrations, but also reflect the mechanical and electronic properties of metal nanoclusters, which holds potential applications in biological sensing and mass detection. Here, we investigated the coherent vibrational dynamics of [Au₂₅(SR)₁₈]^- nanoclusters by ultrafast spectroscopy and revealed the origins of these coherent vibrations by analyzing their frequency, phase and probe wavelength distributions. Strong coherent oscillations with frequency of 40 cm^-1 and 80 cm^-1 can be reproduced in the excited state dynamics of [Au₂₅(SR)₁₈]^-, which should originate from acoustic vibrations of the Au₁₃ metal core. Phase analysis on the oscillations indicates that the 80 cm^-1 mode should arise from the frequency modulation of the electronic states while the 40 cm^-1 mode should originate from the amplitude modulation of the dynamic spectrum. Moreover, it is found that the vibration frequencies of [Au₂₅(SR)₁₈]^- obtained in pump-probe measurements are independent of the surface ligands so that they are intrinsic properties of the metal core. These results are of great value to understand the electron-vibration coupling of metal nanoclusters.     

MFI沸石前驱体和硅酸钠共组装制备水热稳定的管状介孔分子筛

在CTAB模板剂的作用下 ,硅酸钠、铝酸钠和含有MFI纳米簇的沸石前躯体溶液通过S+ I-路线共组装得到了高水热稳定的管状形貌介孔分子筛 .XRD结果显示样品具有类似MCM 41的规则排列六方孔道结构 .在沸水中处理 15 0h后 ,介孔特征仍然保留 ,显示出很好的水热稳定性 .综合SEM和TEM的观察结果 ,此介孔分子筛具有中空的管状形貌 ,平均管长2 .0 μm ,平均直径为 0 .3 0 μm .含有MFI纳米簇的沸石前躯体作为硅源的一部分加入体系中 ,MFI纳米簇伴随来自于硅酸钠的可溶性硅物种共同进入分子筛骨架 ,在提高水热稳定性的同时 ,没有降低六方纳米孔道的规整度 ,也没有对分子筛形貌调变带来不利影响 .MFI纳米簇中 ,硅氧四面体和铝氧四面体的紧密联结方式在进入分子筛骨架时得以保留是水热稳定性提高的主要原因 .作为硅源的另一部分加入的硅酸钠 ,使合成体系pH值足够高 (pH >13 ) ,加入H2 SO4调节体系pH值到10 ,管状形貌的介孔分子筛在逐步中和过程中形成 .通过这种特殊的共组装方法合成介孔分子筛 ,在获得中空的管状形貌的同时显著提高水热稳定性 ,为这种管状形貌介孔分子筛的应用奠定了基础 .     

牛血清蛋白纳米金团簇基于荧光共振能量转移法灵敏检测尿酸

基于纳米金团簇(AuNCs)良好的光学稳定性、生物相容性和简单无毒的制备方法,开发了一种具有高度选择性、高灵敏度且可视化的尿酸(UA)传感器.使用牛血清白蛋白(BSA)作为模板合成了BSA-AuNCs.在尿酸氧化酶的催化下,UA产生化学计量的过氧化氢(H2 O2),导致AuNCs的荧光猝灭.此外,发现BSA-AuNCs...     

多彩金纳米簇:从结构到生物传感和成像

金纳米簇是一种具有发光性能的“类分子”新兴纳米材料.通过调控金原子数目和配体组成性质,金纳米簇可以实现同激发光下不同波段发射,从而展现出“五彩缤纷”的发光特性,这使其被广泛应用于光催化、光学器件、传感和成像等多个领域.因此,开发和优化具有优异发光性能的金纳米簇一直是化学、材料和生物学科的研究热点.本文立足于金纳米簇的发...     

金属纳米簇在CO2光催化还原中的研究进展

化石燃料的大量燃烧不仅造成能源危机，而且排放的二氧化碳（CO2）会使气候变暖。以清洁、储量丰富的太阳光作为能量来源，将CO2光催化还原为高附加值的化学产品是缓解当前环境问题和能源问题的主要方法之一。然而，CO2在常温常压下非常的稳定，因此需要设计并构筑高效光催化剂来捕捉和转化CO2，以达到高效光催化CO2还原的目的。在众多研究的光催化剂中，金属纳米簇因其具有独特的结构特点、优异的物理和化学性质，所以在光催化CO2还原领域得到了广泛的应用。基于此，我们首先对金属纳米簇进行了分类，将其分为贵金属纳米簇和非贵金属纳米簇；然后分别对贵金属和非贵金属纳米簇在光催化CO2还原中的研究进展进行了归纳与总结。本文通过及时全面概述近几年该领域的研究进展，从而为未来研究方向提供新思路。     

Molecularly controlled blending of metals and organic metals with polyolefins for the preparation of materials with modulated optical properties

In this paper, after revisiting previous data on terthiophene molecules, several attempts are described to use metal containing species such as nanoclusters and molecular complexes as dispersed chromophores in the same ethylene polymer matrix in order to extend an approach to new classes of molecules and improve some specific optical responses including fluorescence dichroism and behaviour as linear optical polarizers is evaluated. Comparison with typical linear polarizers from the same polymer and terthiophenes of innovative gold clusters is discussed as well as transition metal complexes.     

金团簇的荧光性质及其生物应用

金纳米团簇作为一类新型纳米材料具有独特的光学特性。当金纳米团簇颗粒的尺寸小到与电子的费米波长（〈1nm）相当时,由于量子尺寸效应,金颗粒会受激发射出荧光。作为一种新型荧光材料,金纳米团簇具有发光颜色随团簇尺寸可调、荧光不易猝灭等许多优势。本文主要综述了金纳米团簇的荧光性质及其在生物标记、生物成像以及生物检测等方面的应用...