硫属近红外纳米晶的水相合成、表征及其应用
发布时间：2018-08-02 09:40
【摘要】：近红外发光的半导体纳米晶具有许多优异的光电特性,使得它们在光电器件、光纤通讯和生物医学等领域具有潜在的应用价值和广阔的应用前景。迄今为止,高质量的近红外发光纳米晶往往通过有机路线合成,水相合成高荧光近红外发光材料研究较少。虽然汞硫属纳米材料是一类性能优良的近红外发光材料,但是合成的HgS纳米晶发光性能极弱,光热稳定性较差。本论文主要集中研究了近红外发光HgS纳米晶的水相合成;开发了基于HgS纳米晶高荧光、稳定的Cd:HgS/CdS纳米晶和HgS/ZnS核壳结构纳米材料,并且展现了它们在光电和生物成像上的应用;另外,一锅法合成了谷胱甘肽稳定的高荧光的近红外Ag2S纳米晶,并将HgS/ZnS核壳纳米晶首次作为荧光探针检测微量Cu~(2+)离子。研究工作主要包括以下五个方面的内容:1.谷脱甘肽稳定的近红外发射的β-HgS纳米晶的水相合成与表征本文发展了一种简单,快速和绿色的室温水相合成路线首次合成了近红外发光的谷胱甘肽稳定的β-HgS纳米晶。所制备的HgS纳米晶具有立方晶型,荧光发射峰位在近红外775 nm到1044 nm波长范围内可调,表现了良好的量子限域效应。与文献所报道的HgS纳米晶相比,我们所制备的谷胱甘肽稳定的HgS纳米晶发光效率大大提高,最大量子效率可达2.8%;同时HgS纳米晶溶液稳定性也得到很大改善,4 ℃冰箱放置4个月后,HgS纳米晶的荧光发射峰仅移动了 9nm,室温放置7天后,荧光发射峰也仅移动了 23 nm。FT-IR谱表明HgS纳米晶所呈现的高的稳定性得益于谷胱甘肽(GSH)分子与纳米晶表面Hg原子之间的多重配位作用。所制备的谷胱甘肽稳定的β-HgS纳米晶发光波段位于近红外区,对已报道的可见光(400-800 nm)和红外光(1000-1600 nm)发射的HgS纳米晶是一个有益补充,赋予了 HgS这一材料更多潜在的应用价值。2.Cd~(2+)调控的高荧光近红外发射HgS纳米晶的合成及其光学应用体相HgS材料是一种科技上非常重要的材料,然而HgS纳米晶弱的荧光发射及其差的稳定性严重阻碍了该材料的潜在应用价值。目前,对HgS纳米晶而言,最突出的问题就是它的不可控生长以及对环境影响敏感的本征表面态。本研究中,我们通过Cd~(2+)离子调控的方法解决了上述问题,首次制备出了稳定的高荧光的Cd:HgS/CdS纳米晶,有效了调控了 HgS纳米晶的带隙水平,使得其本征表面态远离表面,明显降低了周围环境和纳米晶表面态的相互作用,大幅提高了激子跃迁。与"裸露"的HgS纳米晶相比,所制备的Cd:HgS/CdS纳米晶的荧光峰在724 nm～825 nm之间连续可调,最大室温量子产率高达40%,最大半峰宽为95 nm。透射电镜(TEM),X-射线粉末衍射技术(XRD),X-射线光电子能谱(XPS)和原子吸收法(AAS)表征了 Cd:HgS/CdS纳米晶的结构,形貌和元素组成。所制备的Cd调控的HgS纳米晶具有立方晶型结构,由同质的HgCdS合金包被一层薄的CdS壳层组成。进而,我们对Cd:HgS/CdS纳米晶独特的形成机理进行了探讨。这种新合成的高荧光稳定的近红外发射的Cd:HgS/CdS NCs极大扩展了基于HgS纳米晶的应用价值,可直接作为一种防伪用的荧光墨水,也可涂布于蓝光LED表面作为一种优良的光转化器。3.超亮、低毒性近红外发射的HgS/ZnS纳米晶的合成及其生物成像研究迄今为止,高质量的近红外发光纳米晶往往通过有机路线合成,水溶性高荧光的近红外发光材料较少。汞硫属纳米材料虽然是一类优良的近红外发光的材料,但是Hg元素的潜在毒性限制了它们的多样应用前景。本研究中我们通过水相合成方法首次设计合成了一种低毒性的,高荧光稳定的HgS/ZnS核壳结构纳米材料。TEM,XRD和XPS表明了 ZnS壳的生成。在HgS纳米晶表面外延生长一层ZnS壳层后,弱发射的HgS纳米晶转化成了超亮的HgS/ZnS纳米晶,量子产率高达43.8%,并且随着反应pH值的不同HgS/ZnS纳米晶的发射峰位可在785 nm到1063 nm连续可调。重要的是,体外细胞毒性实验明显表明HgS/ZnS纳米晶具有优异的生物相容性,在其孵育浓度高达150 μg·L-1时,细胞存活率仍维持在80%以上,与低毒性Ag2S纳米晶的生物相容性相当。更为重要的是,实验证实低毒性高荧光的HgS/ZnS纳米晶是一种优异的荧光探针,适用于体外和体内成像。应用于裸鼠活体成像时,组织穿透深度达到2 cm,纳米晶的荧光与机体自发荧光有着明显的波长区别,具有优异的对比度。这一新型的超亮的HgS/ZnS纳米晶对生物医学领域高灵敏度、高分辨率和多色成像提供了新的契机。4.谷腕甘肽稳定的近红外发射的Ag2S纳米晶的水相合成与表征本研究采用谷胱甘肽作为稳定剂、AgNO3作为Ag前驱体、硫代乙酰胺(TAA)作硫源,制备了稳定的水溶性近红外Ag2S纳米晶,并且系统地研究了硫源、单体浓度、Ag/S比、反应温度及时间以及配体等合成条件对此近红外Ag2S纳米晶荧光特性的影响。结果表明,采用TAA作为硫源,GSH作为配体,[Ag+]=2 mM,Ag:GSH:S=1:2.5:0.25时,在pH=8的条件下,70 ℃加热30 min得到Ag2S纳米晶荧光强度最强且荧光峰形对称。荧光光谱表征显示此Ag2S纳米晶荧光发射波长为915 nm,量子产率高达4.5%,比文献所报道的发光效率显著提高。粉末X射线衍射和透射电子显微镜表征显示此Ag2S纳米晶为单斜晶系a-Ag2S,尺寸大小约为5 nm。这种合成方法简单廉价,所得到的水溶性近红外Ag2S纳米晶无需经过相转移即可直接应用于生命体系,具有优异的生物相容性,在细胞组织成像等领域有着巨大的应用前景。5.高荧光近红外HgS/ZnS核壳纳米晶作为铜离子的荧光探针首次水相成功合成了谷胱甘肽稳定的HgS/ZnS核壳纳米晶,研究了其与Cu~(2+)的相互作用。实验中观察到,HgS/ZnS核壳纳米晶的荧光能被Cu~(2+)显著猝灭,从而建立了一种测定Cu~(2+)的新方法。干扰实验表明,干扰离子对微量铜的检测几乎没有干扰。在最优化的条件下,纳米晶的荧光强度与Cu24+的浓度在0.125～12.5μmolL-1范围内呈现良好的线性关系,其检测限为0.07μmolL-1。本法提出测定Cu~(2+)的方法具有线性范围宽、灵敏度高、方法简单等特点,适用于实际样品中微量Cu~(2+)的测定,展现了高荧光近红外发射的HgS/ZnS纳米晶在分析领域的应用前景。
[Abstract]:The near infrared luminescent semiconductor nanocrystals have many excellent photoelectric properties, which make them have potential applications and broad applications in the fields of optoelectronic devices, optical fiber communication and biomedicine. So far, high quality near infrared luminescent nanocrystals are often synthesized by organic route, and high fluorescence near infrared hair is synthesized by water phase synthesis. There are few studies on optical materials. Although Hg and s nanomaterials are a kind of near infrared luminescent materials with excellent properties, the luminescent properties of the synthesized HgS nanocrystals are very weak and the thermal stability is poor. This paper mainly focuses on the study of the water phase synthesis of near infrared luminescent HgS nanocrystals, and the high fluorescence and stable Cd:HgS/CdS nanocrystals based on HgS nanocrystals have been developed. The nanomaterials of crystal and HgS/ZnS nuclear shell structure and their applications on Photoelectrical and biological imaging; in addition, one pot method has been used to synthesize the stable and high fluorescence near infrared Ag2S nanocrystals of glutathione, and the HgS/ZnS nuclear shell nanocrystals for the first time as a fluorescence probe to detect the trace Cu~ (2+) ions. The research work mainly includes the following five aspects Content: water phase synthesis and characterization of 1. Valley DEG stable near infrared emission of beta -HgS nanocrystals. This paper developed a simple, fast and green chamber warm water phase synthesis route for the first time to synthesize the near infrared luminescent glutathione stable beta -HgS nanocrystals. The prepared HgS nanocrystals have cubic crystal type and the fluorescence emission peak is near. The infrared 775 nm to 1044 nm wavelengths are adjustable, showing a good quantum confinement effect. Compared with the HgS nanocrystals reported in the literature, the luminescence efficiency of the glutathione stable HgS nanocrystals is greatly improved, the maximum quantum efficiency is up to 2.8%, and the stability of HgS nanocrystalline solution is greatly improved, and the refrigerator is placed at 4 degrees centigrade 4. After a month, the fluorescence emission peak of HgS nanocrystals moved only 9nm. After 7 days at room temperature, the fluorescence emission peak was only moved by 23 nm.FT-IR spectra, indicating that the high stability of the HgS nanocrystals was due to the multiple coordination between the glutathione (GSH) molecule and the nanocrystalline surface Hg atom. The glutathione stable beta -HgS nano was prepared. The crystal luminescence band is located in the near infrared region. It is a beneficial supplement to the reported HgS nanocrystals emitted by the visible light (400-800 nm) and infrared light (1000-1600 nm). It gives HgS this material more potential application value.2.Cd~ (2+) regulated by high fluorescence near infrared emission HgS nanocrystalline crystal and its optical application body phase HgS material It is a very important material in science and technology, however, the weak fluorescence emission of HgS nanocrystalline and its poor stability have seriously hindered the potential application of this material. At present, the most prominent problem for HgS nanocrystals is its uncontrollable growth and the intrinsic surface state sensitive to the environmental impact. In this study, we use Cd~ (2+) ion regulation. The method solved the above problem. The stable high fluorescence Cd:HgS/CdS nanocrystalline was prepared for the first time. The band gap level of HgS nanocrystalline was controlled effectively. The intrinsic surface state was far away from the surface, and the interaction between the surrounding environment and the nanocrystalline surface state was obviously reduced, and the exciton transition was greatly improved. Compared with the bare HgS nanocrystals, The fluorescence peaks of the prepared Cd:HgS/CdS nanocrystals are continuously adjustable from 724 nm to 825 nm, the maximum room temperature quantum yield is up to 40%, the maximum half peak width is 95 nm. transmission electron microscopy (TEM), X- ray powder diffraction (XRD), X- ray photoelectron spectroscopy (XPS) and atomic absorption spectrometry (AAS) characterizing the structure, morphology and element composition of the Cd:HgS/CdS nanocrystals. The HgS nanocrystals prepared by Cd have cubic crystal structure and are composed of a thin CdS shell with homogenous HgCdS alloy package. Then, we discuss the unique formation mechanism of Cd:HgS/CdS nanocrystals. This newly synthesized highly stable near infrared emission Cd:HgS/ CdS NCs greatly extends the HgS nanocrystals. Using value, it can be directly used as a kind of anti-counterfeit fluorescent ink, and can also be coated on the surface of blue light LED as an excellent optical converter.3. super bright, low toxic near infrared emission of HgS/ZnS nanocrystals and bioimaging studies. High quality near infrared luminescent nanocrystals are often synthesized by organic route and high water solubility. There are few near infrared luminescent materials. Although mercury sulfide nanomaterials are excellent near infrared luminescence materials, the potential toxicity of Hg elements limits their application prospects. In this study, we first designed and synthesized a low toxic, highly fluorescent stable HgS/ZnS nuclear shell nanostructure by water phase synthesis. The materials.TEM, XRD and XPS show the formation of ZnS shells. After the epitaxial growth of a ZnS shell on the HgS nanocrystalline surface, the weakly emitted HgS nanocrystals are converted to ultra bright HgS/ZnS nanocrystals with a quantum yield of up to 43.8%, and the emission peaks of the HgS/ZnS nanocrystals can be continuously adjustable from 785 nm to 1063 with the pH value of the reaction pH. Important is the body. The external cytotoxicity test showed that the HgS/ZnS nanocrystals had excellent biocompatibility. When the incubation concentration was up to 150 g. L-1, the cell survival rate remained above 80%, and the biocompatibility of the low toxic Ag2S nanocrystals was equal. The experiment proved that the HgS/ZnS nanocrystals of low toxic Gao Yingguang were a kind of excellent fluorescence. The probe is suitable for in vitro and in vivo imaging. In vivo imaging of nude mice, the tissue penetration depth is up to 2 cm. The fluorescence of nanocrystalline has obvious wavelength difference with the body spontaneous fluorescence, and has excellent contrast. This new super bright HgS/ZnS nanocrystalline provides high sensitivity, high resolution and polychromatic imaging in the field of biomedicine A new opportunity for the water phase synthesis and characterization of Ag2S nanocrystalline with stable near infrared emission of.4. Valley carpi, this study uses glutathione as a stabilizer, AgNO3 as a precursor of Ag and thioacetamide (TAA) as the sulfur source, to prepare a stable water-soluble near infrared Ag2S nanocrystalline, and systematically studies the sulfur source, monomer concentration, Ag/S ratio, and reaction. The effects of temperature, time and ligands on the fluorescence characteristics of the near infrared Ag2S nanocrystals show that TAA is used as a sulfur source, GSH as a ligand, [Ag+]=2 mM, Ag:GSH:S=1:2.5:0.25, at pH=8, and the fluorescence intensity of Ag2S nanocrystalline is the strongest and the fluorescence peak symmetry is obtained at 70 C under the condition of pH=8. The fluorescence spectrum characterization shows that The fluorescence emission wavelength of this Ag2S nanocrystalline is 915 nm, the quantum yield is up to 4.5%, which is significantly higher than that reported in the literature. Powder X ray diffraction and transmission electron microscopy show that the Ag2S nanocrystalline is monoclinic a-Ag2S and the size is about 5 nm.. The synthesis method is simple and cheap, and the water-soluble near infrared Ag2S Nana is obtained. It can be applied directly to the life system without phase transfer. It has excellent biocompatibility and has great potential application in the field of cell tissue imaging..5. high fluorescence near infrared HgS/ZnS nuclear shell nanocrystals have successfully synthesized the stable HgS/ZnS nuclear shell nanocrystals of glutathione by the first aqueous phase of copper ion. The interaction with Cu~ (2+) was observed in the experiment. It was observed in the experiment that the fluorescence energy of the HgS/ZnS nucleation nanocrystals was quenched by Cu~ (2+), thus a new method for determining Cu~ (2+) was established. The interference experiment showed that the interference ions had little interference to the detection of trace copper. Under the optimal conditions, the fluorescence intensity of the nanocrystalline and the concentration of Cu24+ was 0.12 There is a good linear relationship within the range of 5 ~ 12.5 molL-1. The detection limit is 0.07 mu molL-1.. The method proposed for the determination of Cu~ (2+) has the characteristics of wide linear range, high sensitivity and simple method. It is suitable for the determination of trace Cu~ (2+) in the actual samples and shows the application of the Gao Yingguang nanocrystalline in the analysis field of the near infrared emission of Gao Yingguang. View.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1
，
本文编号：2159024
[Abstract]:The near infrared luminescent semiconductor nanocrystals have many excellent photoelectric properties, which make them have potential applications and broad applications in the fields of optoelectronic devices, optical fiber communication and biomedicine. So far, high quality near infrared luminescent nanocrystals are often synthesized by organic route, and high fluorescence near infrared hair is synthesized by water phase synthesis. There are few studies on optical materials. Although Hg and s nanomaterials are a kind of near infrared luminescent materials with excellent properties, the luminescent properties of the synthesized HgS nanocrystals are very weak and the thermal stability is poor. This paper mainly focuses on the study of the water phase synthesis of near infrared luminescent HgS nanocrystals, and the high fluorescence and stable Cd:HgS/CdS nanocrystals based on HgS nanocrystals have been developed. The nanomaterials of crystal and HgS/ZnS nuclear shell structure and their applications on Photoelectrical and biological imaging; in addition, one pot method has been used to synthesize the stable and high fluorescence near infrared Ag2S nanocrystals of glutathione, and the HgS/ZnS nuclear shell nanocrystals for the first time as a fluorescence probe to detect the trace Cu~ (2+) ions. The research work mainly includes the following five aspects Content: water phase synthesis and characterization of 1. Valley DEG stable near infrared emission of beta -HgS nanocrystals. This paper developed a simple, fast and green chamber warm water phase synthesis route for the first time to synthesize the near infrared luminescent glutathione stable beta -HgS nanocrystals. The prepared HgS nanocrystals have cubic crystal type and the fluorescence emission peak is near. The infrared 775 nm to 1044 nm wavelengths are adjustable, showing a good quantum confinement effect. Compared with the HgS nanocrystals reported in the literature, the luminescence efficiency of the glutathione stable HgS nanocrystals is greatly improved, the maximum quantum efficiency is up to 2.8%, and the stability of HgS nanocrystalline solution is greatly improved, and the refrigerator is placed at 4 degrees centigrade 4. After a month, the fluorescence emission peak of HgS nanocrystals moved only 9nm. After 7 days at room temperature, the fluorescence emission peak was only moved by 23 nm.FT-IR spectra, indicating that the high stability of the HgS nanocrystals was due to the multiple coordination between the glutathione (GSH) molecule and the nanocrystalline surface Hg atom. The glutathione stable beta -HgS nano was prepared. The crystal luminescence band is located in the near infrared region. It is a beneficial supplement to the reported HgS nanocrystals emitted by the visible light (400-800 nm) and infrared light (1000-1600 nm). It gives HgS this material more potential application value.2.Cd~ (2+) regulated by high fluorescence near infrared emission HgS nanocrystalline crystal and its optical application body phase HgS material It is a very important material in science and technology, however, the weak fluorescence emission of HgS nanocrystalline and its poor stability have seriously hindered the potential application of this material. At present, the most prominent problem for HgS nanocrystals is its uncontrollable growth and the intrinsic surface state sensitive to the environmental impact. In this study, we use Cd~ (2+) ion regulation. The method solved the above problem. The stable high fluorescence Cd:HgS/CdS nanocrystalline was prepared for the first time. The band gap level of HgS nanocrystalline was controlled effectively. The intrinsic surface state was far away from the surface, and the interaction between the surrounding environment and the nanocrystalline surface state was obviously reduced, and the exciton transition was greatly improved. Compared with the bare HgS nanocrystals, The fluorescence peaks of the prepared Cd:HgS/CdS nanocrystals are continuously adjustable from 724 nm to 825 nm, the maximum room temperature quantum yield is up to 40%, the maximum half peak width is 95 nm. transmission electron microscopy (TEM), X- ray powder diffraction (XRD), X- ray photoelectron spectroscopy (XPS) and atomic absorption spectrometry (AAS) characterizing the structure, morphology and element composition of the Cd:HgS/CdS nanocrystals. The HgS nanocrystals prepared by Cd have cubic crystal structure and are composed of a thin CdS shell with homogenous HgCdS alloy package. Then, we discuss the unique formation mechanism of Cd:HgS/CdS nanocrystals. This newly synthesized highly stable near infrared emission Cd:HgS/ CdS NCs greatly extends the HgS nanocrystals. Using value, it can be directly used as a kind of anti-counterfeit fluorescent ink, and can also be coated on the surface of blue light LED as an excellent optical converter.3. super bright, low toxic near infrared emission of HgS/ZnS nanocrystals and bioimaging studies. High quality near infrared luminescent nanocrystals are often synthesized by organic route and high water solubility. There are few near infrared luminescent materials. Although mercury sulfide nanomaterials are excellent near infrared luminescence materials, the potential toxicity of Hg elements limits their application prospects. In this study, we first designed and synthesized a low toxic, highly fluorescent stable HgS/ZnS nuclear shell nanostructure by water phase synthesis. The materials.TEM, XRD and XPS show the formation of ZnS shells. After the epitaxial growth of a ZnS shell on the HgS nanocrystalline surface, the weakly emitted HgS nanocrystals are converted to ultra bright HgS/ZnS nanocrystals with a quantum yield of up to 43.8%, and the emission peaks of the HgS/ZnS nanocrystals can be continuously adjustable from 785 nm to 1063 with the pH value of the reaction pH. Important is the body. The external cytotoxicity test showed that the HgS/ZnS nanocrystals had excellent biocompatibility. When the incubation concentration was up to 150 g. L-1, the cell survival rate remained above 80%, and the biocompatibility of the low toxic Ag2S nanocrystals was equal. The experiment proved that the HgS/ZnS nanocrystals of low toxic Gao Yingguang were a kind of excellent fluorescence. The probe is suitable for in vitro and in vivo imaging. In vivo imaging of nude mice, the tissue penetration depth is up to 2 cm. The fluorescence of nanocrystalline has obvious wavelength difference with the body spontaneous fluorescence, and has excellent contrast. This new super bright HgS/ZnS nanocrystalline provides high sensitivity, high resolution and polychromatic imaging in the field of biomedicine A new opportunity for the water phase synthesis and characterization of Ag2S nanocrystalline with stable near infrared emission of.4. Valley carpi, this study uses glutathione as a stabilizer, AgNO3 as a precursor of Ag and thioacetamide (TAA) as the sulfur source, to prepare a stable water-soluble near infrared Ag2S nanocrystalline, and systematically studies the sulfur source, monomer concentration, Ag/S ratio, and reaction. The effects of temperature, time and ligands on the fluorescence characteristics of the near infrared Ag2S nanocrystals show that TAA is used as a sulfur source, GSH as a ligand, [Ag+]=2 mM, Ag:GSH:S=1:2.5:0.25, at pH=8, and the fluorescence intensity of Ag2S nanocrystalline is the strongest and the fluorescence peak symmetry is obtained at 70 C under the condition of pH=8. The fluorescence spectrum characterization shows that The fluorescence emission wavelength of this Ag2S nanocrystalline is 915 nm, the quantum yield is up to 4.5%, which is significantly higher than that reported in the literature. Powder X ray diffraction and transmission electron microscopy show that the Ag2S nanocrystalline is monoclinic a-Ag2S and the size is about 5 nm.. The synthesis method is simple and cheap, and the water-soluble near infrared Ag2S Nana is obtained. It can be applied directly to the life system without phase transfer. It has excellent biocompatibility and has great potential application in the field of cell tissue imaging..5. high fluorescence near infrared HgS/ZnS nuclear shell nanocrystals have successfully synthesized the stable HgS/ZnS nuclear shell nanocrystals of glutathione by the first aqueous phase of copper ion. The interaction with Cu~ (2+) was observed in the experiment. It was observed in the experiment that the fluorescence energy of the HgS/ZnS nucleation nanocrystals was quenched by Cu~ (2+), thus a new method for determining Cu~ (2+) was established. The interference experiment showed that the interference ions had little interference to the detection of trace copper. Under the optimal conditions, the fluorescence intensity of the nanocrystalline and the concentration of Cu24+ was 0.12 There is a good linear relationship within the range of 5 ~ 12.5 molL-1. The detection limit is 0.07 mu molL-1.. The method proposed for the determination of Cu~ (2+) has the characteristics of wide linear range, high sensitivity and simple method. It is suitable for the determination of trace Cu~ (2+) in the actual samples and shows the application of the Gao Yingguang nanocrystalline in the analysis field of the near infrared emission of Gao Yingguang. View.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1
，
本文编号：2159024
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