【作者】 李晓民；

【导师】 李林松；

【作者基本信息】 河南大学 ， 物理化学， 2011， 硕士

【摘要】 纳米材料由于其尺寸比较小,在几个到十几纳米,所以会产生许多块体材料所不具备的物理和化学性质,如量子尺寸效应、介电限域效应、表面效应等,使其在光学、电学、磁学和力学等方面获得一些新奇特性。这些新奇的特性使它在发光二极管、激光器、太阳能电池等方面都有很广阔的应用前景。正是由于这些表现出来的新奇特性使得纳米材料科学在近二十年来备受关注,制备各种高质量的纳米材料的方法手段也得以快速发展。通过科学界的努力,发展了许多合成方法,如溶胶-凝胶法、沉淀法、水热法、溶剂热合成法等。在众多合成方法中,选择一种合适的前驱体,使其能够在合成各种无机纳米材料中具有普适性就显得尤为重要。本文主要采用一种普适的有机金属-乙酰丙酮金属盐为前驱体合成各种无机磁性材料、金属材料以及半导体纳米材料。本论文主要工作包括以下几个部分:1、在第二章中,本章介绍了一种尺寸可控合成高质量单分散Fe₃O₄、Ag、以及Fe₃O₄-Ag双功能异质结纳米晶的方法。在合成Fe₃O₄中,采用廉价的十二醇作为还原剂,简单的通过控制各种反应物之间的比例达到对尺寸控制的目的。该方法操作简单,避免了以前“种子二次生长法”的麻烦。在合成Ag纳米晶中,我们采用Agacac为Ag的前驱体,通过控制反应温度达到对Ag纳米晶尺寸的控制。用不同尺寸的Fe₃O₄纳米晶作为种子,还成功的合成出各种尺寸的Fe₃O₄-Ag双功能异质结纳米晶。2、在第三章中,本章主要工作是将乙酰丙酮金属盐作为一种普适的前驱体推广到了各种半导体纳米材料的合成当中。初步的验证了乙酰丙酮金属盐在各种纳米材料合成中的普适性。利用这种方法可以在尺寸可控的基础上,合成出各种高质量三元、二元的半导体纳米晶。另外,通过对表面活性剂种类的选择,可以实现对合成纳米晶形貌的控制。3、在第四章中,以乙酰丙酮金属盐为原料合成Sn-DDT配合物,该配合物可以诱导合成具有良好筒状自组装行为的片状六边形Cu₂S纳米晶。通过实验条件的调节可以得到一维的筒状、二维竹筏状和三维的层状自组装。另外由于Sn-DDT配合物的引入使得各个Cu₂S颗粒之间的距离减小,导电性增强。这种全新的构筑形貌可控的具有良好组装的纳米晶的方法可能会为合成领域以及器件的组装领域提供新的途径。更多还原

【Abstract】 Nanocrystals have attracted a great deal of attention due to their fundamental size- and shape-dependent optical, magnetic, dielectric, and other unique properties, along with their many important technological applications in light emitting diodes （LED）, lasers, solar cells, and so on. Therefore, the development of new techniques to synthesize different kinds of high quality size- and shape- controlled nanocrystals has been widely studied in the last two decades. Until now, there have been many kinds of methods to synthesize the various nanomaterials, which include magnet, metal, and semiconductor nanomaterials, such as sol-gel, deposition, hydrothermal, solvothermal and so on. Though there are many routes to synthesize various nanomaterials, but up to the present there is no one appropriate activity metallic compound was found to synthesize all kinds of nanoparticles. In order to fully investigate the technological potentialities of nanomaterials, the availability of a universal route or metallic compound which can provide great convenience to both flask experiments and a large-scale industrial preparation is urgently required. In this work, metal acetylacetonate [M（acac）x] were choosen as an universal precursors to synthesize a wide variety of nanocrystalsThis thesis includes the following main aspects:In chapter 2, high-quality, monodisperse, and size-controlled Fe₃O₄, Ag, and bifunctional Fe₃O₄/Ag heterodimer nanocrystals （NCs） have been synthesized successfully. In the synthesis of Fe₃O₄ NCs, dodecanol was chosen as the substitute of 1, 2-hexadecanediol and“size control”was achieved by simply adjusting the proportion among the ligands instead of utilizing seed-mediated growth. In the synthesis of Ag NCs, organometallic silver acetylacetonate （Agacac） was used as precursors and tunable particle size could be easily obtained by adjusting the reaction temperatures. By using different sized Fe₃O₄ NCsasseeds, Fe₃O₄/Ag heterodimer NCs with particle sizes tuned from 5 to 16 nm for Fe₃O₄ and 4 to 8 nm for Ag were successfully synthesized and superparamagnetism were maintained.In chapter 3, a general method has been established for the syntheses of semiconductor nanocrystals by using metal acetylacetonates as universal precursors. Using this method, uniform-sized semiconductor nanocrystals including binary and ternary sulfide nanocrystals, binary and ternary selenide nanocrystals are successfully synthesized and the qualities of as-prepared nanocrystals were kept compared with the nanocrystals synthesized by using other sorts of precursors. The shapes of as-prepared nanocrystals are well-controlled by changing the type of organic ligands.In chapter 4, a facile, inexpensive, and reproducible route was demonstrated for the syntheses of self-assembled Cu₂S 1D columnar, 2D raftlike, and 3D stratiform from anisotropic hexagonal nanoplates. It was found that Sn-X complex could inhibit the growth of <001> direction of monoclinic Cu₂S nanocrystals which further induced the formation of the hexagonal lamellar. The conductivity of the self-assembled nanoplates was significantly improved because of the short interparticle spacing （¹.0 nm） linked by the Sn-X complex. We believe that the methodology of constructing self-assembled nanostructures reported in this chapter may turn over a new leaf in device-level manipulation of nanocrystals and many nanocrystal-related potential applications.更多还原