Physicochemical properties of gold nanoparticle crystals

在这个项目的适当时候，我们研究了一种基于表面修饰金纳米粒子自组装的纳米量子晶体的制备，不同于所谓的粒子晶体形成或纳米粒子密集堆积的制备，针对人工设计的量子效应晶体。结果分类如下。1)利用胶体化学技术在水中大规模合成金纳米颗粒。以巯基琥珀酸（MSA）为表面改性剂，建立了用量为0.1 ~ 1g的范围。2)金纳米颗粒晶体的高产率合成。基于DLVO理论，建立了空气/水界面的独立结晶。3)纳米颗粒晶体的光学吸收光谱。我们观察到金纳米颗粒晶体的多晶膜具有不同于孤立颗粒或粉末样品随机包装的典型溶液光谱的特征。在分离粒子中观察到的520 nm宽表面等离子体带被锐化并向低能量侧移动，这表明粒子间的相互作用类似于激子或菁染料的j带。4)金纳米颗粒晶体的STM观察。采用STM技术对纳米金颗粒晶体进行分析，发现纳米金颗粒表面密集覆盖单层msa。5)纳米金颗粒晶体结构评价。采用XRD和TED方法对金纳米颗粒进行了表征，发现其结构致密。6)表面改性剂分子的化学改性。用吡啶羧酸与表面MSA分子发生酯化反应，得到金纳米颗粒单层膜。

In due course of this project, we have studied the preparation of a nano-quantum crystal based upon self-assembling of surface modified gold nanoparticles, different from so-called particle crystal formation or the preparation of dense packing of nanoparticles, aiming the artificially designed quantum effect crystals. The results are classified as follows.1) Large scale synthesis of gold nanoparticles in water by colloidal chemistry technique.The scale of 0.1〜1g quantity was established by using mercaptosuccinic acid (MSA) as a surface modifier.2) High yield synthesis of gold nanoparticle crystals.Free standing crystallization at an air/water interface was developed based on DLVO theory.3) Optical absorption spectrum of nanoparticle crystals.We have observed a characteristic optical spectra in polycrystalline film of gold nanoparticle crystals, which differed from solution spectra typical of isolated particles or random packing of powdered samples. The broad surface plasmon band located at 520 nm observed in isolated particles was sharpened and shifted to lower energy side suggesting strong interparticle interaction likewise of exciton or J-band of cyanine dyes.4) STM observation of gold nanoparticle crystals.STM technique was applied to the particle crystal revealing that the surface of gold nanoparticles are densely covered with monolayer MSA.5) Structural evaluation of gold nanoparticle crystals.XRD and TED method are applied to a good crystal of gold nanoparticles revealing hcp densely packed structure.6) Chemical modification of surface modifier molecules.Esterification reaction was taken place against surface MSA molecules using pyridine carboxylic acid giving monolayer film of gold nanoparticles.