近红外二区发光稀土纳米材料的设计及生物成像应用

近年来,近红外二区(NIR-II,1000~1700 nm)荧光成像因其较高的空间分辨率、较深的组织穿透能力,在分子影像领域引起了广泛的关注。常见的NIR-II发光材料(如有机小分子、共轭聚合物、量子点等)通常具有光稳定性差、荧光量子产率低、斯托克斯位移小、荧光峰宽等问题,限制了这一新型成像技术的进一步发展与应用。稀土纳米材料由于其独特的发光特性,能够较好地克服这些不足,近年来不同结构的稀土纳米材料也逐渐被设计开发并应用于近红外二区荧光成像与检测,展示出了巨大的应用潜力。本综述首先介绍了稀土纳米材料的光学特性,然后按敏化离子的不同(Yb³⁺、Nd³⁺、Er³⁺、Tm³⁺)详细介绍了近红外二区稀土纳米材料的设计方法及相关应用,最后对稀土纳米材料在近红外二区成像领域的进一步发展进行了展望。     

Cr3+ 掺杂近红外荧光材料的研究进展

近红外光谱检测技术具有非侵入性、便携性、响应速度快、效率高等特点,在食品分析、医学监测、虹膜识别和红外成像等领域具有广阔的应用前景。然而,近红外荧光材料面临发射谱带窄、热稳定性差的问题,极大制约了近红外器件的发展。为此,蓝光激发Cr3+掺杂的近红外发光材料在众多方案中优势显著。本综述总结了近年来Cr3+掺杂的宽带近红外荧光材料的最新研究成果,分析了Cr3+掺杂的近红外荧光材料量子效率、发射谱带、电声耦合效应和NIR pc-LED器件的封装,并阐述了Cr3+离子格位占据、敏化发光、发射谱带和热稳定性调控策略。最后,对高效宽光谱发射近红外发光材料的应用前景进行了展望。     

近红外量子剪裁研究进展

目前,发光材料在信息、显示、照明、国防等领域得到了极其广泛的应用．随着人们对发光和发光材料基本科学问题的认识及其广阔而不可替代的应用前景的驱动,发光和发光材料领域在过去100年间迅速发展．量子效率大于1的发光及光功能材料有望在高效发光、等离子体平板显示、高效光纤激光器、高效太阳能光电池等领域得到广泛应用．深入研究光子材料的激发与发光、能量传递与转换、敏化发光与光放大等物理和光学基本科学问题,不但有益于揭示光子材料的一些新现象、新规律,而且将为光子材料与器件的设计与研制奠定理论和方法基础．本文概述了近红外量子剪裁的发展及其材料和相关机理的最近研究进展,主要包括稀土离子单掺体系双光子和三光子级联发射近红外量子剪裁、稀土离子对共掺体系近红外量子剪裁下转换．此外,本文还讨论了量子剪裁及其材料体系的应用、面临的挑战和未来的发展方向．     

Si_5P_6O_(25)∶Tb~(3+)的结构与荧光性质

近年来，掺稀土离子发光材料的研究引起了人们的极大兴趣，已经制备出各种有应用价值的掺稀土发光材料，如掺Tb３＋的三基色发光粉等。由于稀土离子的发光极易受基质的影响，且在不同基质中稀土离子的发光强度不同。所以人们的研究重点集中在改变基质材料上，以减少昂贵稀土的掺杂量，从而提高稀土的发光强度。Tb３＋能发射特征的绿色荧光，其发光强度高，量子效率高，所以围绕铽合成不同基质的发光材料一直是人们所感兴趣的研究课题。ZhangH．X．等犤１犦制备了掺杂Tb３＋、Eu３＋的Zn２SiO４体系发光材料，该材料像广泛应用于电视和C…     

稀土近红外二区纳米荧光影像探针及其生物医学应用※

与传统的荧光生物成像相比, 近红外二区(NIR-II)荧光生物成像技术具有空间分辨率高、信噪比高、成像深度大、自发荧光低、生物损伤小等优势, 在活体成像、疾病诊断、无创治疗等领域应用前景广泛. 在众多的NIR-II荧光纳米材料中, 稀土近红外二区纳米荧光探针(NIR-II Ln-NPs)因具有化学稳定性和光稳定性好、发射带窄、发光颜色和寿命可调等优点受到研究人员的广泛关注. 因此, 本文系统介绍了NIR-II Ln-NPs的设计策略、控制合成、发光调控、表面修饰、以及在生物医学应用方面的最新研究进展, 并对该领域的技术难题及未来发展趋势进行了探讨.     

钙黄绿素对Yb(Ⅲ)近红外发光的敏化作用研究

近红外发光可用于荧光免疫分析、激光系统及光信号放大等方面,三价镧系离子配合物的近红外发光的研究引起了人们的兴趣。近红外发光稀土离子的发射能级低,特别容易受到溶剂分子的碰撞而产生荧光猝灭作用,通过优化配体的结构,提高配体对中心稀土离子的配位作用,尽     

稀土纳米材料在高分辨活体成像及诊疗中的应用

荧光成像具有时空分辨率高、 反馈快、 非侵入和无电离辐射等优点, 是一种重要的生物成像技术. 与传统用于荧光成像的可见光和近红外一区(NIR-I, 600~950 nm)相比, 近红外二区(NIR-Ⅱ, 1000~1700 nm)窗口具有低生物组织散射系数和低生物自发荧光, 采用NIR-Ⅱ光进行活体荧光成像能有效提高成像的分辨率、 信噪比和穿透深度. 稀土纳米颗粒(RENPs)具有大斯托克斯位移、 高化学稳定性、 可调的荧光寿命以及较窄的发射带, 是一种重要的荧光成像探针. 近年来, 一系列具有优异的NIR-Ⅱ发光性能的稀土纳米材料被用于高分辨活体荧光成像. 本文综合评述了近年来RENPs用于高分辨活体成像及诊疗中的研究进展, 概述了RENPs的掺杂调控、 基质晶格选择和复合敏化等NIR-Ⅱ发光增强策略, 介绍了其在多种生物医学场景中的靶向聚集、 荧光传感和疾病治疗等功能, 并总结了其在多路成像、 多模态成像和疾病诊疗中的应用. 最后, 简要分析了RENPs在未来生物医学应用中面临的挑战和发展的方向.     

近红外发光稀土配合物及杂化材料研究进展

稀土因其特殊的物理和化学性质,在信息技术、能源技术、生物技术等高科技领域及国防建设等方面都起着非常重要的作用,中国作为稀土大国,十分重视对稀土材料的研究和开发。稀土离子近红外发光(750～1700 nm)在激光和光纤通讯、医学诊断、免疫分析等热门领域的潜在应用,受到了科研人员的极大关注。稀土离子本身发光极弱,通过分子内传能有机配体可以敏化稀土离子发光,但稀土配合物常受外界干扰,其稳定性较差,若将其与凝胶、介孔材料、离子液体等无机基质复合,得到具有良好光、热稳定性和化学稳定性的有机/无机杂化材料。总结了近些年来近红外发光稀土配合物及近红外发光稀土杂化材料的研究进展,并对其发展前景进行了展望。     

氮(氧)化物荧光粉研究进展

氮氧化物荧光粉材料具有高发光效率、可被可见光有效激发、荧光特性可设计性强、热稳定性高和环境友好等诸多优点,因此成为白光LED用荧光体的重要候选材料.近年来,国际材料学界掀起了稀土掺杂氮氧化物荧光粉的研究热潮,并取得了一系列创新性研究成果.本文综述了各种新型氮氧化物荧光粉的制备方法,重点分析了各类稀土掺杂氮氧化物荧光粉的发光特征及其研究进展,最后探讨了氮氧化物荧光粉的研究发展方向.通过改变稀土掺杂离子周围的晶体场环境实现对荧光体发光性能的裁剪设计、激活离子在荧光体基质材料中所占据结晶位置的确定、高质量红光氮氧化物荧光体的研发等将是氮氧化物荧光体未来研究的主要方向.     

等离子体增强上转换发光及其应用

稀土上转换纳米材料（UCNPs）是一类在近红外光激发下发出可见光的纳米材料。与有机荧光染料、量子点等发光材料相比,UCNPs具有化学稳定性高、光稳定性强、荧光寿命长、反斯托克斯位移大、发光谱带窄和光穿透深度大等诸多优点,在生物成像、传感器、激光器、光动力疗法和太阳能电池等领域有潜在的应用价值。但是由于UCNPs激活离子的吸收截面太小,导致其发光效率偏低,限制了UCNPs的进一步应用。因而如何提高上转换发光强度成为当前的研究热点。针对上述问题,本文系统阐述了金属表面等离子体共振（SPR）增强上转换发光领域的研究进展。首先介绍了SPR增强上转换发光的三种机制,随后重点介绍了化学法和物理法这两种SPR-UCNPs体系的构建方法以及其在太阳能电池、生物成像、生物检测、光热治疗和光催化等领域的应用。文章最后指出了SPR增强上转换发光领域存在的不足和未来的研究方向。     

Lanthanide-doped inorganic nanocrystals as luminescent biolabels

Trivalent lanthanide ions (Ln(3+)) doped inorganic nanocrystals (NCs) have currently attracted reviving interest and come to the forefront in nanophotonics owing to their potential applications in diverse fields such as luminescent biodetection and bioimaging. As an alternative to conventional biolabels, Ln(3+)-doped NCs show superior features including large stokes shift, multicolor fine-tuning, narrow emission band widths, high photostability, and low toxicity. Particularly, the long-lived luminescence and distinct upconversion (UC) of Ln(3+)-doped NCs are desirable for various bioapplications. The long-lived luminescence of Ln(3+) combined with time-resolved technique can efficiently suppress the interference from short-lived background, resulting in a high signal-to-noise ratio (S/N) and background-free measurements. Near-infrared excited UC emissions of Ln(3+) can bring no autofluorescence and no photodamage to cells or tissues, and thus UC NCs have been regarded as one of the most useful in vivo optical contrast agents. In this review, we outline the most recent development of Ln(3+)-doped NCs as biolabels from the controlled synthesis and surface functionalization of NCs to their bioapplications in heterogeneous and homogeneous biodetection as well as in vitro and in vivo bioimaging.     

Host Differential Sensitization toward Color/Lifetime-Tuned Lanthanide Coordination Polymers for Optical Multiplexing

Optical multiplexing based on luminescent materials with tunable color/lifetime has potential applications in information storage and security. However, the available tunable luminescent materials reported so far still suffer from several drawbacks of low efficiency or poor stability, thus restraining their further applications. Herein, we demonstrate a strategy to develop efficient and stable lanthanide coordination polymers (LCPs) with tunable luminescence as a new option for optical multiplexing. Their multicolor emission from green to red and naked-eye-sensitive green emission with tunable lifetime (from ca. 300 to ca. 600 μs) can be controlled by host differential sensitization and energy transfer between lanthanide ions. The quantum efficiencies of developed samples range from around 20 % to 46 % and the luminescence intensity/lifetime appear quite stable in polar solvents up to ten weeks. Furthermore, with the aid of inkjet printing and concepts of luminescence lifetime imaging and time-gated imaging, we illustrate their promising applications of information storage and security in spatial and temporal domains.     

Novel antennae for the sensitization of near infrared luminescent lanthanide cations

Near Infrared (NIR) luminescence is useful for many applications ranging from lasers, telecommunication to biological imaging. We have a special interest for applications in biological media since NIR photons have less interference with such samples. NIR photons can penetrate relatively deeply in tissues and cause less damage to biological samples. The use of NIR luminescence also results in improved detection sensitivity due to low background emission. The lower scattering of NIR photons results in improved image resolution. NIR emitting lanthanide compounds are promising for imaging because of their unique properties such as sharp emission bands, long luminescence lifetimes and photostability. Here, we review our efforts to develop novel sensitizers for NIR emitting lanthanides. We have employed two global strategies: (1) monometallic lanthanide complexes based on derivatives of salophen, tropolonate, azulene and pyridine; and (2) polymetallic lanthanide compounds based on nanocrystals, metal-organic frameworks and dendrimers complexes.     

稀土/L型沸石主-客体发光功能材料的研究进展

沸石微孔晶体材料作为客体功能物种的主体材料在主-客体组装化学中发挥着越来越重要的作用,在微型激光器、非线性光学、生物成像、光放大及光显示等高技术领域已显示出广阔、诱人的发展前景.本文介绍国内外,特别是河北工业大学在稀土/L型沸石主-客体杂化功能材料的组装、结构及其发光性能的研究工作,具体包括：稀土有机配合物在L沸石孔道内的组装、L型沸石-有机高分子透明杂化发光材料的制备及稀土有机配合物诱导控制的L型沸石自组装等.此外,本文对稀土/L型沸石主-客体杂化发光功能材料的研究进行了展望.     

Covalent linking of near-infrared luminescent ternary lanthanide (Er(3+), Nd(3+), Yb(3+)) complexes on functionalized mesoporous MCM-41 and SBA-15

The near-infrared (NIR) luminescent lanthanide ions, such as Er(III), Nd(III), and Yb(III), have been paid much attention for the potential use in the optical communications or laser systems. For the first time, the NIR-luminescent Ln(dbm)(3)phen complexes have been covalently bonded to the ordered mesoporous materials MCM-41 and SBA-15 via a functionalized phen group phen-Si (phen-Si = 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline; dbm = dibenzoylmethanate; Ln = Er, Nd, Yb). The synthesis parameters X = 12 and Y = 6 h (X denotes Ln(dbm)(3)(H(2)O)(2)/phen-MCM-41 molar ratio or Ln(dbm)(3)(H(2)O)(2)/phen-SBA-15 molar ratio and Y is the reaction time for the ligand exchange reaction; phen-MCM-41 and phen-SBA-15 are phen-functionalized MCM-41 and SBA-15 mesoporous materials, respectively) were selected through a systematic and comparative study. The derivative materials, denoted as Ln(dbm)(3)phen-MCM-41 and Ln(dbm)(3)phen-SBA-15 (Ln = Er, Nd, Yb), were characterized by powder X-ray diffraction, nitrogen adsorption/desorption, Fourier transform infrared (FT-IR), elemental analysis, and fluorescence spectra. Upon excitation of the ligands absorption bands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide ions through the intramolecular energy transfer from the ligands to the lanthanide ions. The excellent NIR-luminescent properties enable these mesoporous materials to have potential uses in optical amplifiers (operating at 1.3 or 1.5 mum), laser systems, or medical diagnostics. In addition, the Ln(dbm)(3)phen-SBA-15 materials show an overall increase in relative luminescent intensity and lifetime compared to the Ln(dbm)(3)phen-MCM-41 materials, which was explained by the comparison of the lanthanide ion content and the pore structures of the two kinds of mesoporous materials in detail.     

Lanthanide Metal–Organic Frameworks Showing Luminescence in the Visible and Near‐Infrared Regions with Potential for Acetone Sensing

The luminescent properties of a family of lanthanide metal–organic frameworks LnL ( Ln =Y, La–Yb, except Pm; L =4,4′‐({2‐[(4‐carboxyphenoxy)methyl]‐2‐methylpropane‐1,3‐diyl}bis{oxy})dibenzoic acid) have been explored, and the energy‐transfer process in the compounds has been carefully analyzed. The visible‐emitting Tb_0.08Gd_0.92L and the near‐infrared (NIR)‐luminescent Yb_0.10Gd_0.90L show excellent optical performances and can be considered as fluorescent probes for acetone sensing based on luminescence quenching effects arising from host–guest interactions. Moreover, GdL exhibits a strong second harmonic generation (SHG) signal 6.1 times that of potassium dihydrogen phosphate (KDP) and an outstanding phase‐matchable effect. These lanthanide compounds combining fluorescent and nonlinear optical (NLO) properties could meet further requirements as multifunctional materials.     

Luminescent properties and recent progress in applications of lanthanide metal-organic frameworks

Lanthanide metal-organic frameworks(Ln-MOFs), which is composed of organic bridging ligands and Ln3+ions/clusters, is an important component of luminescent MOFs. Compared with transition metal ions,lanthanide ions have a higher coordination number and abundant coordination geometry. Moreover, LnMOFs have special characteristics such as good porosity, topological diversity, high surface area and highly adjustable structure. The energy transfer(ET) process in Ln-MOFs could be easily affected by th...     

Recent advances in the sensitized luminescence of organic europium complexes

In this paper, recent advances in the synthesis, mechanism of sensitized emission, and luminescent properties of organic lanthanide complexes are reviewed. Stress is put on the progress in the development of organic europium complexes and their nanoparticles with excellent visible-light-sensitized and two-photon-sensitized Eu^III luminescence properties. These are of increasing importance because bioanalysis or bioimaging techniques based on such labeled materials will combine the advantages of high sensitivity, high signal-to-noise ratio, deep penetration, and low photodamage to biological samples. In addition, the application of long-wavelength-sensitized luminescence of organic lanthanide complexes and their nanoparticles in bioimaging is discussed.     

Lanthanide-centered organic-inorganic hybrids through a functionalized aza-crown ether bridge: coordination bonding assembly, microstructure and multicolor luminescence

This work focuses on the synthesis of a series of chemically bonded lanthanide/inorganic/organic hybrid materials (CE-15-Si-Ln, CE-16-Si-Ln, CE-18-Si-Ln) containing a novel aza-crown ether organic component. The materials show red emission (Ln = Eu), green emission (Ln = Tb) and near-infrared (NIR) luminescence (Ln = Nd). Three functional molecular precursors (denoted as CE-15-Si, CE-16-Si, CE-18-Si) have been synthesized with two or three N-substituted pendant arms containing chelating groups which can not only fulfill the high coordination numbers of Ln(3+) ions but also form an inorganic Si-O-Si network with tetraethoxysilane (TEOS). The resulting amorphous materials exhibit regular uniform microstructures for the organic and the inorganic components which are covalently linked through Si-O bonds via a self-assembly process. These hybrids present strong luminescent intensities in red, green and NIR ranges by embedding selected Ln(3+) ions into the hybrid system, which may lead to potential applications in organic electroluminescence displays, light emitting devices, functional membranes or chemical/biomedical sensors.