基于磁性FePt纳米粒子-发光量子点的核壳纳米结构构筑和半导体界面层对其磁光性质的调控研究

Fabrication of high performance magnetic and luminescent core/shell nanostructures and understanding of the electronic interaction between magnetic and luminescent nanoparticles is the key for their biomedical and magneto-optoelectronic applications. In this project several kinds of semiconductor shells and SiO2 as well as some organic functional molecules with different thicknesses are used to coat FePt nanoparticles to change the electronic coupling between FePt nanoparticles as the core and luminescent quantum dots as the shell, improve the crystalline quality of the materials,control charge transport and stability and obtain high performance magnetic and luminescent nanocomposites with highly efficient photoluminescence and strong magnetic properties. The research works includes the following respects: 1) the preparation of FePt nanoparticles coated with semiconductor shells such as ZnO, TiO2, ZnS, ZnSe and SiO2 as well as some organic functional molecules and study on the effect of the shells on the morphology and magnetic properties of FePt nanoparticles. 2) the growth of highly efficient luminescent quantum dots such as ZnSe, CuInS2 and their Mn doped nanocrystals on the surface of the FePt/semiconductor shell nanoparticles and study of the size and structure of the quantum dots and the thicknesses of emissive layers on the magnetic and luminecent properties of the nanostructures.It also includes the study of magnetic particles, interface semiconductor layer barriers, and their energy level alignment on the luminescent properties of the nanocomposites. 3) the understanding of the charge transport between the magnetic nanoparticles and luminescent quantum dots and optimization of fabricating magnetic and luminescent core/shell nanostructures for achievement of high performance nanocomposites. These make us better understand the control of the charge transport in nanocomposites for designing and preparing the magnetic and luminescent core/shell nanostructures. Therefore, the study on these questions above is very important for us to further optimize these nanostructures of magnetic and luminescent core/shell nanostructures and improve their performances for applications of magnetic resonance and optical imaging.

构建高性能磁性荧光核壳纳米结构是其应用于生物医药和光电子领域的关键问题。本项目将利用半导体、有机配体和绝缘材料作为界面势垒层，改变荧光半导体量子点壳层与磁性FePt纳米粒子核之间的电子耦合，改善材料结晶质量和控制电荷传输以及稳定性，获得高效发光和强磁性的复合纳米材料。首先在各种粒径FePt粒子表面包覆ZnO，TiO2，ZnS和SiO2壳层以及有机配体，研究粒子结构和磁性变化。再在强磁性粒子表面制备ZnSe和CuInS2及其Mn掺杂量子点发光层，研究量子点尺寸、结构和发光层厚度对复合纳米结构磁性和发光性质的影响。同时研究磁性粒子和界面势垒层及其能级结构对发光性质的影响，了解FePt粒子与发光量子点层之间的电荷输运过程，优化合成方法和条件，构建最佳的复合纳米结构。上述关键科学问题的研究，对改善磁性和发光效率，发展高性能磁性荧光复合纳米结构和开展它们的磁共振及光学成像研究具有重要科学意义。

制备高质量的荧光量子点、磁性纳米粒子及磁性荧光复合纳米结构，改善磁性和发光效率，是其应用于生物医药和光电子领域的关键问题。在本项目中，我们获得了以下主要研究结果：.1) 合成了三种代表性的发光纳米材料如CuInS2、ZnInS和Mn或Cu单掺或共掺ZnInS核壳量子点，CsPbBr3和Mn掺杂CsPbCl3钙钛矿纳米晶和Al掺杂ZnO氧化物纳米粒子。基于Cu掺杂ZnInS和ZnCdS、MnCu共掺杂ZnInS量子点和Cu掺杂ZnInS核壳量子点等，获得了高性能的白光LED。研究了这些纳米材料的结构、形貌及量子点纳米晶溶液、薄膜和量子点LED的发光性质、稳定性，探讨了能量传递、电荷转移过程和发光原理。.2) 制备了FePt/SiO2、FePt/MgO、FePt/TiO2核壳纳米粒子和FePt薄膜，FePt-Fe3O4、CoxFe3-xO4、Co2P、FeCoP纳米粒子，铁氧体/SiO2纳米粒子和薄膜等，获得了样品的结构、形貌、晶粒尺寸、磁相变和磁相互作用等有意义的结果，并将哑铃状FePt-Fe3O4纳米粒子用于多巴胺的电化学检测。.3) 获得了高效发光的CuInS2/ZnS核壳量子点-FePt纳米粒子复合材料和Cu掺杂的ZnInS量子点-FePt/MgO核壳纳米粒子复合体系，研究了材料的结构、磁性和发光性质，探讨了CuInS2/ZnS核壳量子点-FePt纳米粒子复合薄膜的发光猝灭和电子转移过程，以及MgO壳层对Cu掺杂的ZnInS量子点和FePt纳米粒子之间电子转移的影响。.上述研究结果对量子点及量子点LED、磁性纳米粒子、以及发光量子点-磁性纳米粒子复合结构的研制具有重要的科学意义，为它们的实际应用提供了物理、化学基础和制备技术。

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