稀土核壳结构纳米颗粒的制备及发光性能研究

发布时间：2018-05-23 13:17

本文选题：核壳 + 稀土纳米颗粒　；参考：《贵州大学》2015年硕士论文

【摘要】：本文以多元醇为溶剂,稀土氯化物为原料,NaOH为沉淀剂,合成出了稀土离子掺杂的球形的Gd2O3纳米核,然后利用正硅酸乙酯(TEOS)和3-氨丙基三乙氧基硅烷(APTES)水解缩聚的作用在纳米核表面包裹上聚硅氧烷壳层形成Gd2O3:Tb3+/SiOx,壳层的包覆能够提高纳米颗粒的稳定性,并为下一步与生物分子连接,实现生物医药方面的应用提供了可能。为制备出发光性能优良的核壳结构纳米材料,首先研究了两种稀土掺杂离子(Tb3+和Eu3+)对Gd2O3纳米核发光性能的影响,随后研究了不同包覆比例(包覆试剂中的Si与前驱体中Gd的摩尔比例)以及不同分子量PEG溶剂对Gd2O3:Tb3+/SiOx发光性能的影响。利用马尔文激光粒度仪、TEM、SEM、荧光光谱等手段对样品的尺寸、微观形貌和发光性能进行表征,对影响纳米颗粒尺寸及发光性能的参数进行了优化。实验结果表明:(1)Eu3+和Tb3+共掺杂Gd2O3的发射光谱有545nm和612nm两个较强的发射峰,固定5%Tb3+掺杂,随着Eu3+掺杂比例的升高,两发射峰强度在Eu3+掺杂2%时达到最大,超过2%后开始下降,表明存在Eu3+→Tb3+的能量传递且Eu3+的猝灭浓度为2%;固定2%Eu3+掺杂,随着Tb3+掺杂比例的升高,545nm的发射峰强度在5%Tb3+掺杂时达到最大,超过5%后发光又开始减弱,分析是发生了Tb3+的浓度猝灭,而随着Tb3+掺杂浓度的上升,612nm处发射峰强度逐渐降低,验证了产物中Eu3+→Tb3+的能量传递。综合看来Gd2O3:5%Tb3+,2%Eu3+的发光性能最好。(2)包覆比例越大,纳米颗粒的尺寸及壳层的厚度越大。随着包覆比例的升高,发光强度先略微下降然后上升,至包覆比例为4:1时发光强度达到最大,超过4:1后发光又开始减弱。包覆比例为4:1时Gd2O3:Tb3+/SiOx的发光性能最佳。(3)不同分子量PEG溶剂中合成的Gd2O3∶Tb3+/SiOx尺寸区别较大,PEG200溶剂最大程度的促进了纳米颗粒的长大。随着Gd2O3∶Tb3+/SiOx尺寸的增大,激发和发射强度均而增强。
[Abstract]:In this paper, the spherical Gd2O3 nanoparticles doped with rare earth ions were synthesized by using polyol as solvent and rare earth chloride as raw material, NaOH as precipitant. Then the polysiloxane shell was formed by the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethoxy silane (APTES) on the surface of the nanocrystalline nucleus, and the coating of the shell could improve the stability of the nanoparticles. It also provides the possibility for the next step to connect with biomolecules and realize the application of biomedicine. In order to prepare core-shell nanomaterials with excellent luminescence properties, the effects of two rare earth doped ions (Tb3 and Eu3) on the photoluminescence properties of Gd2O3 nanostructures were studied. The effects of different coating ratios (molar ratio of Si in the coating reagent to Gd in the precursor) and different molecular weight PEG solvents on the luminescence properties of Gd2O3:Tb3 / SiOx were studied. The size, micromorphology and luminescence properties of the samples were characterized by Ma Erwen laser particle size analyzer (TEM-SEM) and fluorescence spectroscopy. The parameters affecting the size and luminescence properties of the nanoparticles were optimized. The experimental results show that there are two strong emission peaks of 545nm and 612nm in the emission spectra of Gd2O3 doped with 545nm and Tb3. The intensity of the two emission peaks increases with the increase of the ratio of Eu3 doping, and the intensity of the two emission peaks reaches the maximum when Eu3 doping is 2%, and decreases after more than 2%. The results show that the energy transfer of Eu3 Tb3 exists and the quenching concentration of Eu3 is 2. The intensity of emission peak at 545nm of fixed 2%Eu3 doping reaches the maximum with the increase of Tb3 doping ratio, and the emission intensity decreases again after more than 5% of Tb3 doping. The concentration quenching of Tb3 occurs and the emission peak intensity decreases with the increase of Tb3 doping concentration at 612nm, which verifies the energy transfer of Eu3 Tb3 in the product. It is shown that the larger the ratio of luminescent properties of Gd2O3:5%Tb3 ~ (2 +) and EU _ (2) is, the larger the size of nanoparticles and the thickness of shell are. With the increase of the coating ratio, the luminescence intensity decreased slightly and then increased. The luminescence intensity reached its maximum at 4:1, and began to weaken after 4:1. When the coating ratio is 4:1, the luminescence property of Gd2O3:Tb3 / SiOx is the best. 3) the Gd2O3:Tb3 / SiOx synthesized in PEG solvent with different molecular weight has a large difference in size. The solvent PEG200 can promote the growth of nanoparticles to the greatest extent. The excitation and emission intensities increase with the increase of Gd2O3:Tb3 / SiOx size.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O482.31;TB383.1

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