颗粒间距可控、形貌均匀的周期性贵金属纳米点阵列制备新方法及其SERS活性研究

The periodic noble metal naoarry has great potential applications in the field of mirco-nano optoelectronic devices due to the special optical nonlinearity effects. The morphology and spacing of nanoparicles are the decisive factors to the properties and application values of nanoarray. However, till now, the control of morphology and spacing of the nanoparticles is still the key problem which attracted the widely interest among the researchers. In this project, the fabrication technique of noble metal nanodots array based on the AAO template is presented. The controllable preparation of AAO template is the beginning. Then, the laser irradiation technique is used to the modification of morphology for the noble metal nanoparticles. The nanoparticles have been modified to have a good match to the size of AAO holes. And interestingly, the modified nanoparticles will be organized onto the hole of the AAO tempalte skillfully. Through the changes of AAO hole size and center-to-center spacing, the goal of controllable spacing and size for nanoparticles could be realized. And also,the properties of localized surface plasmon resonance and electric field enhancement will be investigated systematically.The SERS mechanism will be discussed and the laser irradiation effect on the modification of morphology for noble metal nanoparticles will be analysed. Usually,the performance of the nanoarry is dependent on the preparation technology. Based on the feeback from the performance, a simple and lowcost method of making periodic noble metal nanoparticle array, which has controllable spacing and uniform morphology, will be formed. What's more, the results of this project will provide the technique foundation for industry manufacture of ordered metal nanoparticals array and application of mirco-nano optoelectronic devices.

周期性贵金属纳米点阵列具有独特的非线性光学效应，在微纳光电器件领域有极为广阔的应用前景。其中，纳米颗粒单元的形貌、间距控制是决定阵列性能及其应用价值的关键，也是本领域研究的热点和难点。本项目提出基于AAO模板的贵金属纳米点阵列构筑技术，以AAO模板的可控制备为切入点，以激光辐照对贵金属纳米颗粒形貌的均匀优化处理为突破口，以纳米颗粒与AAO模板纳米孔的匹配控制为主线，巧妙地将纳米颗粒组装架构在AAO模板的孔洞上，通过改变AAO模板的孔洞尺寸以及孔心距，实现阵列结构中纳米颗粒尺寸以及间距的可调控性。系统研究此阵列结构的局域表面等离激元共振及电场增强特性，揭示其SERS活性增强机制，从工艺-性能-工艺出发，提出一套简单高效、低成本、颗粒间距可控，形貌均匀的周期性贵金属纳米颗粒阵列制备的新方法，并为有序金属纳米颗粒阵列的工业化制备及其器件化应用提供拥有自主知识产权的技术基础。

周期性贵金属纳米点阵列具有独特的非线性光学效应，在微纳光电器件领域有极为广阔的应用前景。其中，纳米颗粒单元的形貌、间距控制是决定阵列性能及其应用价值的关键，也是本领域研究的热点和难点。经过大量的实验探索和理论研究，本项目发明了一套基于阳极氧化铝模板（AAO）的周期性金、银球形纳米粒子阵列低成本、大面积制备技术，实现了纳米颗粒单体尺寸和阵列间距的可调控性，其中，金、银纳米颗粒单元尺寸直径在60-100 nm可控，间距在5-40 nm可控。发现此阵列具有很好的SERS灵敏度和可重复性，且具有奇特的非偏振依赖特性。基于点群和点阵理论，依托FDTD理论模拟，揭示了周期性贵金属球形纳米粒子阵列的SERS偏振特性与阵列中纳米球周期性排布的对称性密切相关，不同点阵结构的贵金属纳米球阵列表现出完全不同的SERS偏振特性，二维点阵结构中，初基单斜、初基正交、底心正交和初基四方点阵结构的纳米球阵列均展示出偏振依赖SERS特性，只有基于本项目提出的初基六方点阵结构的贵金属纳米球阵列具有非偏振依赖SERS特性，这在SERS实际检测应用中具有极大价值，相关结果得到了同行的高度评价。采用光辐照技术对纳米单体形貌进行有效控制，发现准分子激光辐照可使得不规则形状的银纳米颗粒变为各向同性的均匀球形，氙灯和汞灯连续光源辐照则制备出棒状、三角板状等各向异性银纳米颗粒，分别采用改进的“光热-相变”理论和“碎裂-连接-生长”的演化模型对形貌演化的物理过程进行了详细阐述。此外，作为本项目的拓展内容，提出了无支撑层的超薄阳极氧化铝模板（UTAM）转移技术，并在Si、ITO等功能性衬底上制备小间距黑莓状金银纳米结构，此结构具有优异的SERS活性，在痕量检测，太阳能电池等光电器件中具有较大的应用潜力。在本项目的支持下，建立了一套完整的周期性贵金属纳米球阵列制备体系，发表SCI 论文10 篇，申请中国发明专利9项，已获授权5项，申请澳大利亚国际发明专利1项，已公开。