Synthesis of discretely shaped nanostructures and their application in surface enhanced Raman detection

目前用于合成纳米晶体的种子生长方法通常产生具有简单形态和功能的对称纳米晶体。将不同的形状集成到分层纳米结构中将允许纳米级物体添加新的功能以执行多个并行任务。在本研究中，我们采用Au奈米片作为晶种来生长岛状的Au奈米线阵列。纳米线的形成与晶种的形状无关。通过在Au纳米片上引入强结合配体4-巯基苯甲酸（MBA），将岛状生长限制为一维生长，并在纳米片上沉积出纳米森林状二级结构。重要的是，二级结构的形成被认为是独立的种子形状。最后，还证明了具有密集热点的分级纳米结构为化学检测提供了强的表面增强拉曼散射。

The current seeded growth approaches for synthesis of nanocrystals often produce symmetrical nanocrystals with simple morphology and function. Integration of different shapes into a hierarchical nanostructure would allow nanoscale objects to add new functionalities for performing multiple parallel tasks. In the present study, we employed Au nanoplate as the seed for island growth of Au nanowire arrays. The formation of nanowires is independent of the seed shape. By introducing a strong binding ligand, 4-mercaptobenzoic acid (MBA), to the Au nanoplates, the island growth was restricted into one-dimensional growth, and nano-forest-like secondary structure was deposited on the nanoplates. Importantly, the formation of the secondary structure was found to be independent of the seed shape. Finally, it has also been demonstrated the hierarchical nanostructures with dense hot-spots provides strong surface-enhanced Raman scattering for chemical detection.