基于NaYF4:Yb,Er多功能纳米材料的制备及其特性研究

	基于NaYF4:Yb,Er多功能纳米材料的制备及其特性研究
	张瑾
学位类型	博士
导师	李斌
	2014-07
学位授予单位	中国科学院大学
学位专业	凝聚态物理
摘要	上转换荧光材料是一类重要的稀土发光材料,它能够通过多光子机制将低频率激发光转换成高频率发射光，在固体激光器、光存储器、传感器、太阳电池和三维立体演示等领域都有着重要的应用。近年来，以上转换荧光作为检测信号的荧光传感器的研究逐渐受到化学家，环境学家，生物学家的重视，相关报道日益增多。稀土上转换荧光纳米材料具有毒性小、化学稳定性高、光稳定性好、Stokes 位移大、吸收和发射带窄、寿命长等优点，另外近红外光作为其激发光源，对生物组织几乎无损伤、组织穿透深度大、同时可以避免生物样品自体荧光的干扰和散射光现象，从而降低检测背景，提高信噪比。这些优异的性能使上转换荧光传感器在环境化学，临床毒理学，生物化学等方面都有着非常好的应用前景。因此对于上转换纳米材料的功能化设计、合成已经成为化学、材料、生物医学等领域的研究热点。本论文在调研大量文献的基础上，利用简单的高温有机溶剂法、水热法制备了六角相的β-NaYF4纳米晶，将探针分子及光敏剂分子以吸附、共价嫁接的方式与其相结合，分别制备了对特定金属离子具有选择性识别能力及能够产生单线态氧的多功能复合上转换纳米材料。本论文取得的主要成果如下：　　1、利用高温有机溶剂法合成了六角相的β-NaYF4纳米晶，将其与对铜离子具有高选择性的RB-hydrazide相结合，在近红外光作为激发光源条件下，β-NaYF4的上转换绿光发射光谱与RB-hydrazide-Cu的激发光谱有好的光谱重叠，为二者之间的能量转移提供了可能性。通过上转换发光的减弱及探针分子的荧光增强实现对铜离子的光学传感。该体系能够有效、快速地识别铜离子，同时近红外激发光源具有背景荧光干扰低，对生物组织几乎无损伤，组织穿透深度大等优点，使其在分析检测，生物领域方面有潜在的应用价值。　　2、用简单的水热、溶胶-凝胶法合成了二氧化硅包覆的β-NaYF4@SiO2核壳结构纳米材料，通过共价嫁接的方式将RB-hydrazide荧光探针分子固载到二氧化硅表面，得到了对汞离子具有传感性能的核壳型的纳米复合材料。所制得的复合材料在近红外激发下能够显示明亮的上转换绿光发射，同时对重金属汞离子具有较好的选择性、较高的灵敏度，并且其荧光强度表现出对汞离子浓度的线性响应。这种纳米复合材料的上转换光学性质、汞离子传感性能使它们在分析化学、生物化学等领域有潜在的应用价值。　　3、用简单的方法合成了介孔二氧化硅包覆的β-NaYF4@SiO2@mSiO2核壳结构纳米材料，得到的介孔材料具有一致有序的多孔孔道结构、高的比表面积及大的孔体积，有利于提高对光敏剂分子的装载吸附。装载有光敏剂Rose bengal分子后，该复合材料用近红外光照射，绿色的上转换发光能进一步激发光敏剂分子，激发态的光敏剂分子可以与周围的氧气分子相互作用，生成对癌细胞具有杀伤力的单线态氧，并且通过间接的方法检测到了单线态氧的产生。所得到的复合材料有望在生物化学、生物医学方面有所应用。
其他摘要	Rare-earth upconversion luminescence materials, converting low frequency excitataion light to high frequency emission light via multiphoton mechanism, have important applications in the solid state laser, optical storage, sensors, solar cells and three-dimensional presentation. In recent years, the researches of fluorescence sensors based on upconversion luminescence as detection singal have gradually gathered attention by chemists, environmentalists, biologists. Upconversion nanomaterials have shown many advantages, including low toxicity, high chemical stability, good light stability, large Stokes shift, narrow absorbance and emission bands, simultaneously, near-infrared (NIR) irradiation has lower photo damage effect, a larger penetration depth in tissues, and at the same time, it can avoid the autofluorescence interference of biological sample and light scattering phenomenon, which reduces background light and improves signal-to-noise ratio. These excellent properties make upconversion fluorescence sensors possessing very good application prospect in environmental chemistry, clinical toxicology and biochemistry fields. So functional design and synthesis of upconversion nanomaterials have become a research hot spots in the chemical, material and biomedical fields. On the basis of a vast amount of literature research, this thesis synthesize hexagonal phase β-NaYF4 nanocrystals using simple high temperature organic solvent method and hydrothermal method, and then probe molecules and photosensitizer molecules can be combined with upconversion nanomaterials in the form of adsorption or covalently grafting, the obtained multifunctional nanocomposites display good ability to recognize specific metal ion or produce singlet oxygen. The major achievements obtained are as follows: 　　1. Hexagonal phase β-NaYF4 nanocrystals was first prepared through high temperature organic solvent method, and then combined with RB-hydrazide possessing high selectivity for copper ions. Upon NIR light as excitation source, excitation spectrum of RB-hydrazide-Cu overlaps well with upconversion green luminescence of β-NaYF4 nanocrystals, indicating the possibility for the energy transfer between them. Decreased upconversion luminescence intensity and increased fluorescence intensity of probe molecules realize the optical sensing for copper ion. The system can effectively and quickly identify copper ions, simultaneously, NIR irradiation displays the advantages of slight background light interference, lower photo damage effect, a larger penetration depth in tissues, which endows the system with further potential application for copper ion detection in analytical and biological fields. 　　2. Core/shell-structured β-NaYF4@SiO2 nanorods with very thin and uniform silica coatings have been prepared via simple hydrothermal and sol-gel approaches. Because of the upconversion luminescence nanorods core (β-NaYF4) and fluorescent probe (RB-hydrazide) immobilized onto silica shell by covalent bonding, the nanocomposites exhibit good sensing property for mercury ion. Under NIR excitation, nanomaterials show bright upconversion green emission, as well as good selectivity and high sensitivity for mercury ion. As a fluorescence chemosensor, the obtained nanomaterial displays a good linearity between the fluorescence intensity of probe molecules and the concentration of mercury ion. NIR-to-Vis upconversion luminescence and good selectivity for mercury ion, endow the nanocomposites with further potential applications for mercury ion detection in analytical chemistry and biochemistry fields. 　　3. Ordered mesoporous silica encapsulating core-shell structured upconversion luminescence nanomaterials β-NaYF4@SiO2@mSiO2 have been successfully synthesized by the surfactant-assistant sol-gel coating method. The mesoporous silica shells possess uniform pore size distribution, high BET surface area and pore volume, which is favorable for loading photosensitizer molecules. Upon irradiation by NIR light, photosensitizer molecules (Rose bengal) activated by the green emission from upconversion nanorods can interact with surrounding oxygen molecules and produce singlet oxygen, which can cause oxidative damage to biological substrates and ultimately cell death. The generation of singlet oxygen is evaluated using fluorescent indicator. These properties may develop nanocomposites potential application in biochemistry and biomedical aspects.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41500
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	张瑾. 基于NaYF4:Yb,Er多功能纳米材料的制备及其特性研究[D]. 中国科学院大学,2014.

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