无机纳米稀土发光材料的制备方法*

无机纳米稀土发光材料作为一种重要的发光材料,由于具有独特的光、电和化学性质,使其在高性能磁体、发光器件、显示、生物标记、光学成像和光学治疗等方面得到了广泛的应用。稀土发光材料的这些性质与材料的尺寸和形状密切相关,近年来研究者已经利用多种合成方法制备了不同形状的纳米稀土发光材料,包括纳米线、纳米棒、纳米管、纳米纤维和纳米片等。本文综述了无机纳米稀土发光材料的几种常用的制备方法,包括水热/溶剂热法、有机/无机前驱体热分解法和超声辅助合成法等,评述了这些方法的优缺点,并结合课题组在无机纳米稀土发光材料制备方面的工作,对无机纳米稀土发光材料制备方法的发展进行了展望。     

《化学通报》网络版(Chemistry Online)2005年第11期论文摘要

[w123]具有纳米结构的有机发光材料研究进展**Progress in Research on Organic Nanomaterials for Luminescence赵雷黄维*(复旦大学先进材料研究院上海200433)对有机纳米发光材料制备方法以及材料的性能作了较为全面的综述。有机纳米发光材料由于存在分子间作用力(范德华力)或氢键以及具有小的Frenkel激子半径,与无机半导体纳米微粒以及纳米金属有着很大的区别,具有自己独特的光电性能,同时又兼具了有机发光材料响应速度快、可进行分子设计和纳米材料的尺寸效应等优点,在新型光电器件方面具有潜在应用前景。综合研究现状,本文也提出了该…     

稀土上转换纳米发光材料研究进展

上转换纳米发光材料(UCNPs)是一种能在长波长光激发下发出短波长光的发光材料.在较多的研究中UCNPs在980 nm红外光激发下,能发出不同颜色的可见光,可以显著提高信噪比,所以UCNPs在三维立体显示、上转换激光器、红外探测、防伪识别、生物检测等诸多领域都具有广阔的应用前景.从稀土上转换纳米发光材料的基质和稀土离子及其光学性能方面概述了近几年稀土上转换纳米发光材料的研究进展.     

Na2SiF6对Er3+, Yb3+共掺杂上转换发光材料颗粒度的影响

合成了Er3+, Yb3+共掺杂的纳米级上转换发光材料.针对稀土离子Er3+, Yb3+共掺杂上转换发光材料的制备过程, 研究了络合剂和Na2SiF6对控制最终产物颗粒度的作用, 指出络合剂和Na2SiF6的共同作用有利于合成出粒度分布比较均匀的纳米级上转换发光材料, 讨论了Na2SiF6的作用机制, 并简单阐述了上转换发光材料的发展和应用.     

纳米稀土发光材料的光学特性及软化学制备

概述了纳米稀土发光材料具有的、为传统发光材料无法媲美的5个光学特性，介绍了纳米稀土发光材料的软化学制备方法。通过对各种方法进行比较，指出了其优缺点，并对该类材料在超微化、高密度集成、高空间分辨率等方面的前景进行了探讨及展望。     

基于介孔纳米粒子模板合成兼有荧光和近红外发光的稀土核-壳结构纳米材料

利用单分散性良好介孔SiO2纳米粒子为模板,选择Y2O3为基底,同时掺杂可见区红光中心Eu3+和近红外区Er3+(1.54 μm)发光中心,成功制备特殊结构的核壳多功能发光纳米材料. 光谱测试表明这种核壳材料同时具有可见区发光和近红外发光的双重性质. 表明Y2O3可作为红光Eu和近红外发光Er的良好基底材料. 该方法可以大大降低纳米发光材料中稀土元素的使用量,降低发光材料的成本,并且该核壳结构材料密度相对较低,易于分散在有机溶剂或者水中,在药物释放和多功能生物标记等方面有着潜在的应用价值.     

沉淀法合成纳米晶上转换发光材料Y_2O_2S:Yb,Er

采用沉淀法在不同温度下合成了纳米上转换发光材料Y2O2S∶Yb,Er,运用XRD、TEM和上转换发光光谱对其进行表征。结果表明,使用该法在700℃即能合成纳米上转换发光材料Y2O2S∶Yb,Er,随着合成温度的升高,产物的粒径从60到120nm逐渐增大。上转换发光光谱显示该材料主要有2个发射带,其中红光发射的中心波长位于668nm,绿光发射的中心波长位于525和550nm。此外,对材料的上转换发光过程进行了探讨。     

Sr3Al2O6:Eu2+红色发光纳米晶的新型形貌与发光性能的研究

对于稀土发光纳米晶来讲,产品颗粒尺寸与形貌不仅对发光性能有影响,而且直接影响其应用[1,2].如颗粒尺寸在1～10 μm之间且形貌接近于球形的发光微米晶在涂屏时发光效率是最高的,而具有新型微观结构与形貌的稀土发光纳米晶,如纳米线、纳米棒及具有自组装特性的花晶等纳米结构材料由于在纳米发光器件方面有着潜在的应用价值,已成为当今纳米科学的研究焦点.     

金属纳米团簇的合成及其光致发光性质的调控

金属纳米团簇是一种既具有出色光物理性质,又具有良好生物相容性的零维材料.利用配体对团簇的热力学稳定产物的选择性和还原剂动力学调控可以合成出结构多样的金属纳米团簇,在光学材料、生物医学和催化材料等领域展示出颇具潜力的应用前景.但金属纳米团簇的稳定性差、发光弱等缺点限制了其实际应用,因此通过聚集诱导发光效应和超分子自组装协同调控金属纳米团簇的稳定性及光学性质,可以构筑出结构与发光可控的金属纳米团簇组装体,有效促进金属纳米团簇的实际可用性.本文简要介绍了不同配体保护的金属纳米团簇的合成,阐述了金属纳米团簇的光致发光性质,总结了聚集诱导发光效应对团簇超分子组装体光致发光性质的影响规律,并分析提出了当前研究仍存在的问题及对未来探究的展望.     

金属卤化物钙钛矿纳米晶高效发光二极管的制备与器件性能优化

金属卤化物钙钛矿作为一类新型的离子型直接带隙半导体材料在电致发光二极管(LED)中有着重要应用前景. 但实现其应用的前提在于金属卤化物钙钛矿材料需要保持高的发光效率和好的稳定性. 为了提高金属卤化物钙钛矿作为LED发光层的激子结合效率, 从而提升其发光效率, 设计和合成金属卤化物钙钛矿纳米晶材料是一个有效途径. 目前, 基于纳米晶材料设计的金属卤化物钙钛矿LED在绿光和红光(包括近红外光)范围已经展现了高的发光亮度和外量子效率(EQE), 其中最高EQE已经超过了20%, 但其稳定性仍无法满足器件应用的要求. 此外, 更值得关注且更重要的是, 蓝光钙钛矿LED的发光亮度和EQE目前仍然不高. 如何制备高效、 稳定的金属卤化物钙钛矿纳米晶LED, 特别是蓝光LED, 是一个具有重大应用前景且具有挑战性的课题. 本文重点介绍了金属卤化物钙钛矿纳米发光层的结构设计和合成方法及金属卤化物钙钛矿LED的研究进展, 分析了金属卤化物钙钛矿LED不稳定的原因, 并对金属卤化物钙钛矿LED研究面临的挑战和未来发展方向进行了总结与展望.     

Optical emission from C60-molecule-coupled Si nanocrystallites

Using C60 molecule as a kind of surface-passivated agent to modify the electronic structure of Si nanocrystallites in porous silicon, we disclose that this kind of C60/nanocrystalline Si coupling system can show a strong blue emission at approximately 460 nm when stored in air for more than one year. After a full characterization of the photoluminescence properties, we propose a luminescent center in the SiOx layer at the surface of a Si nanocrystallite. It is a pair consisting of an oxygen vacancy and an interstitial oxygen. The interstitial oxygen also forms a peroxy linkage with a neighboring lattice oxygen. Radiative recombination of carriers photogenerated from Si nanocrystallite cores in the luminescent centers results in the observed blue photoluminescence. Neutron irradiation experiments support our assignment of the blue emission mechanism. This work improves the understanding of the origin of blue emission from silicon/oxygen-related nanostructured materials.     

The study of preparation and luminescence of polymethyl methacrylate/rare earth composite luminescent materials

The alkaline-earth–rare-earth–aluminate systems phosphors are the new types of phosphors, which process very bright, safer, and excellent photoluminescence. Because of hydrolysis, however, the capacity of luminescent materials will fall down and the use value of luminescent materials will also be lost. Water-resistant polymers, which can form a kind of water-resistant clad on the surface of luminescent material powder, will solve this problem and the significance of its application is important. In this study, the polymethyl methacrylate (PMMA)/rare earth composite luminescent materials were prepared through grafting emulsion polymerization of methyl methacrylate onto the surface of luminescent materials. To study the structure and properties of the PMMA/rare earth composite luminescent materials, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and photoluminescent properties were measured. From the curves of FTIR and TGA, we can find that the organic parts are attached with the inorganic parts in the PMMA/rare earth composite luminescent materials. The results of luminescent decay curves show that the resistance to water of the PMMA/rare earth composite luminescent materials is much better than that of the unmodified luminescent materials because the organic parts had been grafted on the luminescent materials.     

Liquid-Phase Synthesis of Iron Oxide Nanostructured Materials and Their Applications

Owing to their high natural abundance, low cost, easy availability, and excellent magnetic properties, considerable interest has been devoted to the synthesis and applications of iron oxide nanostructured materials. Liquid-phase synthesis methods are economical and environmentally friendly with low energy consumption and volatile emissions, and as such have received much attention for the preparation of iron oxide nanostructured materials. Herein, the liquid-phase synthesis methods of iron oxide nanostructured materials including the co-precipitation method, microemulsion method, conventional hydrothermal and solvothermal methods, microwave-assisted heating method, sonolysis method, and other methods are summarized and reviewed. Many iron oxide nanostructured materials, self-assembled nanostructures, and nanocomposites have been successfully prepared, which are of great significance to enhance their structure-dependent properties and applications. The specific roles of liquid-phase chemical reaction parameters in regulating the chemical composition, structure, crystallinity, morphology, particle size, and dispersive behavior of the as-prepared iron oxide nanostructured materials are emphasized. The biomedical, environmental, and electrochemical energy storage applications of iron oxide nanostructured materials are discussed. Finally, challenges and perspectives are proposed for future investigations on the liquid-phase synthesis and applications of iron oxide nanostructured materials.     

近红外稀土荧光在功能材料领域的研究进展

稀土近红外荧光材料具有特征发射峰尖锐、光稳定性好和毒性低等特点。近年来,稀土近红外荧光材料在光纤通讯、激光系统、生物分析传感器及生物成像等方面的应用价值日渐突显,引起了研究者们的极大关注。特别是稀土近红外荧光材料已发展成一种新兴的荧光标记材料,并有希望替代有机染料和量子点应用于生物分析和医学成像。基于稀土近红外发光的荧光探针具有低自荧光背景、宽斯托克斯位移、强抑制光漂白、深层穿透组织和短暂分辨的优势,有潜力成为高灵敏度、高选择性的检测手段。利用稀土离子制备的各种荧光材料,如上转换纳米晶、介孔材料、脂基胶体、离子液体、离子胶体、金属有机框架等,由于荧光敏化机理不同,其近红外荧光性能也各有千秋。然而,稀土近红外荧光的真正挑战仍是提高近红外发光的量子效率。本文结合近红外荧光领域的最新进展,综述了不同的稀土近红外荧光设计思路,介绍了各种近红外稀土荧光功能材料,阐述了稀土离子在近红外荧光功能材料中的优势,并展望了稀土近红外荧光材料的发展前景。     

Solution,Solid-State Two Step Synthesis and Optical Properties of ZnO and SnO<Subscript>2</Subscript> Nanoparticles and Their Nanocomposites with SiO<Subscript>2</Subscript>

Nanostructure luminescent ZnO and SnO₂ materials are prepared by a two-step solid-state method based on the solution preparation of the macromolecular precursors ZnCl₂·Chitosan and SnCl₂·Chitosan having different ratios (1:1, 1:5 and 1:10), their pyrolysis under air at 800 °C. The pyrolytic ZnO and SnO₂ nanomaterials show a dependence of the particle size, morphology and luminescent properties with the ratio [metal/polymer] in the MCl₂·Chitosan precursors. Thus, ZnO semiconductor materials exhibit luminescence spectra with several emission at 440 nm corresponds to a radiative transition of an electron from the shallow donor level of oxygen vacancies, and the zinc interstitial, to the valence band. On the other hand, the photoluminescence spectrum of the nanostructured SnO₂ shows an intense blue luminescence at a wavelength of 420 nm which may be attributed to oxygen-related defects that have been introduced during the growth process of the nanoparticles. Additionally, whereas SnO₂ was successfully incorporated into SiO₂ structure (SnO₂//SiO₂) by pyrolysis of solid-state mixtures of the precursors SnCl₂·Chitosan in the presence of SiO₂, the same reaction carried out with ZnCl₂·Chitosan precursors led to a mixture of Zn₂SiO₄ and SiO₂. Thus, this new methodology yields nanostructured semiconductor materials, ZnO and SnO₂, suitable for optoelectronic and sensor solid-state devices.     

Recent advances in organic pressure-responsive luminescent materials

Pressure is a powerful tool to regulate the molecule aggregation and intermolecular interactions. Organic luminescent materials under high pressure can produce rich phenomena,which have many potential applications.     

Recent advances in organic pressure-responsive luminescent materials

Organic luminescent materials are very sensitive to external stimuli,such as pressure,temperature,and electric field.The luminescent properties of some organic luminescent materials significantly change under high pressure.Some materials may show luminescence discoloration,whereas some may exhibit luminescence enhancement.These properties have many potential applications in anticounterfeiting,force sensor,data recording and storage,and luminescent devices,thereby greatly attracting the attention of scientists.In this review,the progress of research on these materials at high pressure in recent years is summarized.     

Luminescence of Nanosized Supramolecular Material of Mesoporous Molecular Sieve and Samarium （Ⅲ） Complex

IntroductionThe synthesis of mesoporous silica has greatlyexpanded the possibilities for the design of the porestructure materials[1] . Because of their large sur-face areas and porosity,these materials have greatpotential application in environmental and industri-al fields.A greatmany significant advanced resultshave been achieved in this field including the syn-theses of the related materials[2— 4] ,the develop-ment of the novel properties[5— 8] ,the discovery ofnew theories on synthetic c…     

Nanostructured materials in potentiometry

Potentiometry is a very simple electrochemical technique with extraordinary analytical capabilities. It is also well known that nanostructured materials display properties which they do not show in the bulk phase. The combination of the two fields of potentiometry and nanomaterials is therefore a promising area of research and development. In this report, we explain the fundamentals of potentiometric devices that incorporate nanostructured materials and we highlight the advantages and drawbacks of combining nanomaterials and potentiometry. The paper provides an overview of the role of nanostructured materials in the two commonest potentiometric sensors: field-effect transistors and ion-selective electrodes. Additionally, we provide a few recent examples of new potentiometric sensors that are based on receptors immobilized directly onto the nanostructured material surface. Moreover, we summarize the use of potentiometry to analyze processes involving nanostructured materials and the prospects that the use of nanopores offer to potentiometry. Finally, we discuss several difficulties that currently hinder developments in the field and some future trends that will extend potentiometry into new analytical areas such as biology and medicine.