【作者】 时雪钊；

【导师】 王春明； 高鸿钧；

【作者基本信息】 兰州大学 ， 分析化学， 2011， 博士

【摘要】 纳米材料由于其独特的物理化学特性,在光学、催化、传感器敏感界面构建等方面有重要应用,在世界范围内逐步成为热门研究课题。本论文利用电化学沉积方法和有机液相合成法合成了几种纳米薄膜和颗粒状纳米材料,并使用多种表征手段对这些纳米材料的结构及性能进行了分析表征,主要内容包括：1)本文采用电化学原子层沉积(EC-ALD)技术,在多晶金基底上生长了单层Sb2Se3化合物,以循环伏安、计时电流技术研究了在单层硒修饰的金基底上单层锑的形成及溶出过程动力学。循环伏安数据表明单原子层锑的形成经历二维成核或生长过程,其溶出也表现为二维过程。计时电流数据也得出同样结果。采用电化学方法在导电玻璃基底上制备了Sb2Se3化合物,并研究了其生长过程动力学,并且对其形貌,晶体结构以及元素组成进行了分析。2)采用简单的一步单相法在有机溶剂中制备出单分散的银纳米颗粒。通过调节前驱体的浓度以及前驱体和表面活性剂之间的比率调控了银纳米颗粒的尺寸。用TEM, HR-TEM以及XRD分析了银纳米颗粒的形貌和晶体结构,运用XPS、FTIR等分析手段对银纳米颗粒的表面吸附情况进行分析,结果表明油胺分子通过氮原子与银化学键合包覆在银纳米颗粒表面。以紫外可见光谱和表面增强拉曼散射研究了银纳米颗粒的表面等离子共振(Surface Plasmon Resonance SPR)性质。3)在合成银纳米颗粒基础上,通过调节反应中的表面活性剂,以CTAB代替TOP,在苄醚中成功制备合成了高产率的银纳米方块,并对其形貌,晶体结构和表面吸附情况作了研究。对形成银纳米方块的各种因素进行了系统研究,并且提出了形成纳米方块的可能机理,Br-离子在银纳米方块的形成中起到关键作用。本工作中所得到的银纳米方块具有良好的表面等离子共振和表面增强拉曼散射特性,在生物传感、表面增强拉曼散射等方面有潜在的应用价值。4)在比较低的温度下,以油胺为溶剂和还原剂成功地制备出单分散、不同组分的AuPd合金纳米颗粒。用XRD分析合金纳米颗粒的结构,纳米颗粒中两种元素形成fcc结构的合金。UV/Vis结果表明,两种合金纳米颗粒均有SPR吸收峰,但相对Au纳米颗粒SPR吸收峰发生了蓝移。用XPS表征了合金纳米颗粒两种元素的键合情况,结果表明合金纳米颗粒为两种元素所形成的合金。以Au3Pd和Au2Pd纳米颗粒作为表面增强拉曼基底,测试了4-MBA分子的SERS特性,结果表明合金纳米颗粒具有很好的SERS特性。5)采用种子辅助法合成了不同长径比的金纳米棒。金纳米棒通过表面毛细作用力形成高度有序的自组装阵列。金纳米棒表面对拉曼散射光有显著的增强作用,对2-萘基硫醇和罗丹明6G两个分子的拉曼散射增强因子为5-6个数量级,并且增强因子随长径比的增加而减小。紧密堆积的金纳米棒的表面等离子共振相互耦合,在两纳米棒之间的空隙处形成很大的局域增强的电磁场,从而导致了拉曼散射信号的增强。更多还原

【Abstract】 Synthesis of nanomaterials with controlled structure and morphology has been pursued with great effort recently, driven by both the excitement of understanding new chemistry and the potential hope for practical applications. In this paper, electrochemical and organic phase synthesis method were used to fabricate several nanofilms and nanoparticles, and many instruments, including SEM, TEM, HR-TEM, UV/Vis, SERS were employed to characterize the as-synthesised nanomaterials:1) Electrochemical atomic layer deposition (EC-ALD) technique was employed to fabricate the first layer of Sb2Se3 compound on gold substrate. Cyclic votammgyclic and chronoamperometric method were used to investigate the formation mechanism of first layer of Sb2Se3 formed on gold electrode through EC-ALD method. The deposition and stripping of antimony on Se-modified gold electrode proceed by a two-dimensional nucleation and growth mechanism in the underpotential region. Additionally, Sb2Se3 was also fabricated on ITO substrate through electrochemical method and the growth kinetics was investigated according to current density-time data. The morphology, crystalline structure and element component was also studied.2) Monodisperse silver nanoparticles with narrow size distribution are synthesized by direct reaction of the silver acetate and oleylamine in Benzyl ether. The particle sizes are controlled by tuning the precursor concentration and the ratio between precursor and surfactants. Surface plasmon resonance (SPR) phenomena and surface enhanced Raman scattering (SERS) observed from the silver nanoparticles are found to be size-dependent. As the particle size increases, the SPR peak red shifts and the SERS signal intensities increases.3) Monodisperse silver nanocubes were synthesized by the reduction of silver acetate in hydrophobic solvent benzyl ether. Cetyltrimethylammonium bromide (CTAB) was used as surfactants in the synthesis process. Transmission electron microscopy (TEM), high resolution TEM and X-ray diffraction (XRD) was used to investigate the morphology, crystalline structure and surface adsotption chemistry of the silver nanocube. The factors for the formation of silver nanocube were investigated systematically and we found that the Br- played critical role in the formation of silver nanocube. The silver nanocubes show good surface Plasmon resonance and surface enhanced Raman scattering properties, which have promising applications in biosensor, SERS, and biomedicine.4) AuPd bimetal nanoparticles ware successfully synthesized at low themperature. In the synthesis, oleylamine was used as reductant and also solvent. X-Ray dispesion was used to study the crystalline structure of the bimetal nanoparticles and show that alloy was formed in the AuPd nano particles. UV/Vis and X-ray photoelectronic were used to investgated the SPR properties and surface adsorption chemistry. The SERS properties of the two bimetal nanoparticles was studied using 4-mercaptobenzoic acid molecule as model molecules and the results show that the two bimetal nanoparticles could served as effective SERS substrates.5) Gold nanorods with aspect ratios from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure in a large scale on silicon substrates through capillary force induced self-assemble behavior during solvent evaporation. The gold nanorod surface exhibits strong enhancement effect to Raman scattering spectroscopy. By changing the aspect ratio of Au nanorods, it was found that the enhancement factors decrease with the increase of aspect ratios. The observed Raman scattering enhancement is strong and it should be ascribed to the surface plasmon coupling between closely packed nanorods, which may result in huge local electromagnetic field enhancements in these confined junctions.更多还原