高电荷态重离子辐照控制金纳米颗粒形态变化的研究

Au Nanoparticles(NPs) of different shapes have attracted much interest due to their unique physical properties which were dominated by the size, shape, crystal structure and surface properties of the individual NP.As a consequence, its development drives the size modification technology to a high level. When highly charged ions (HCIs) impact on a solid target, the high Coulomb potential energy they carried will be delivered into a few atomic layers of the surface and result in a particle deformation, hence the HCI beam shaping technique is becoming a powerful tool to manipulate matter at the nanometer scale. This project aims at constructing a setup on the highly charged atomic physics platform in the Heavy Ion Research Facility in Lanzhou (HIRFL) for research about utilizing highly charged heavy ions with energy of hundreds keV impacting onto NPs to control theie deformation. Rutherford Backscattering Spectrometry(RBS) and the surface plasmon resonance(SPR) analysis was performed to determine the unique optical properties related with the shape, size, and depth distribution of the deformed Au NPs. In order to explore the deformation rules and understand the interaction mechanism between NPs and HCIs, different irradiation parameters such as dose, energy, charge state of the HCIs will be applied. Simultaneously, the target surface will be measured so as to investigate the energy loss of HCIs on the target surface as well as the mechanism of the potential deposition. Apart from contributing to accumulating experience of experimental technology, this project will also provide important data on the relationship between the Au NPs' shapes or physical properties and the irradiation parameters and finally can serve as a referee for fundamental theory in the interaction between HCIs and matter.

金纳米颗粒的独特物理、化学性质与其尺寸、形状、晶体结构等密切相关,其制备与调控技术一直备受关注。高电荷态重离子入射固体表面时，所携带的极高势能可以在表面nm量级内沉积并引起颗粒发生形变，这使得重离子辐照成为一种有效控制纳米颗粒形貌的方法。本项目旨在兰州重离子加速器国家实验室高离化态原子物理实验平台上，利用不同剂量和能量的高荷电重离子辐照吸附于基底表面的球形金纳米颗粒使之发生形变，观测金纳米颗粒形状和尺寸变化与辐照参数的关系，通过卢瑟福背散射（RBS）和表面等离子体共振（SPR）分析研究受辐照后形变的金纳米颗粒独特的光学性质，探索高电荷态重离子调控金纳米颗粒形态变化的规律和作用机制。同时，研究高荷电重离子在靶材料表面的能损和势能沉积的作用机理等。本项目将为金纳米颗粒形态变化及其物理特性与辐照参数的关联性，及重离子与物质相互作用的基础理论和潜在应用研究积累实验技术和重要参考数据。

项目组成功制备了形状尺寸均匀直径分别为15 nm，30nm和48 nm的金纳米颗粒，衬底分别为C，Si和SiO2。利用兰州重离子加速器国家实验室320 kV-ECR离子源提供的高品质Ar离子和Xe离子，如选取Xeq+(q=3,5,7,10,13,17,21)离子的入射能量范围为0.5 MeV-4 MeV，辐照靶材样品，获得了较为丰富、精度高的实验数据，通过数据分析、建立理论模型，较为深入系统地研究并揭示了受 HCIs 辐照后的 Au NPs形状、尺寸与辐照参数的关联性和辐照变形后不同形态的 Au NPs的光学性质，实现了 HCIs 辐照对 Au NPs光学性质的调控的目标。在此过程中研究了不同入射条件下金纳米颗粒的形貌变化规律，包括辐照作用过程中的动能、势能的影响。同时研究电子发射产额随不同辐照参数的变化关系。系统地分析实验数据，建立相关理论模型，探索中低能高电荷态重离子控制金纳米颗粒形貌的变化规律和机制。为研究玻尔速度附近离子与物质作用中的能损，电荷效应等方面提供了重要的实验参考数据；为金纳米颗粒形态变化及其物理特性与辐照参数的关联性、重离子与物质相互作用的基础理论及潜在应用研究积累了实验技术和重要参考数据。