Chen Guoxin, Guo Changjin, Cheng Yao, Lu Huanming, Cui Junfeng, Hu Wanbiao, Jiang Rongrong, Jiang Nan
Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19A Yuquan Rd., Shijingshan District, Beijing 100049, China.
Nanomaterials (Basel). 2019 Mar 1;9(3):328. doi: 10.3390/nano9030328.
How a heavily charged metal nanocrystal, and further a dual-nanocrystals system behavior with continuous electron charging? This refers to the electric dynamics in charged particles as well as the crystal growth for real metal particles, but it is still opening in experimental observations and interpretations. To this end, we performed an in-situ electron-beam irradiation study using transmission electron microscopy (TEM) on the Au nanocrystals that freely stand on the nitride boron nanotube (BNNT). Au nanocrystalline particles with sizes of 2⁻4 nm were prepared by a well-controlled sputtering method to stand on the BNNT surface without chemical bonding interactions. Au nanoparticles presented the surface atomic disorder, diffusion phenomena with continuous electron-beam irradiation, and further, the long-range motion that contains mainly the three stages: charging, activation, and adjacence, which are followed by final crystal growth. Firstly, the growth process undergoes the lattice diffusion and subsequently the surface-dominated diffusion mechanism. These abnormal phenomena and observations, which are fundamentally distinct from classic cases and previous reports, are mainly due to the overcharging of Au nanoparticle that produces a surface activation state in terms of high-energy plasma. This work therefore brings about new observations for both a single and dual-nanocrystals system, as well as new insights in understanding the resulting dynamics behaviors.
一个带大量电荷的金属纳米晶体，以及进一步的具有连续电子充电的双纳米晶体系统的行为是怎样的？这涉及到带电粒子中的电动力学以及真实金属粒子的晶体生长，但在实验观察和解释方面仍有待探索。为此，我们使用透射电子显微镜（TEM）对自由站立在氮化硼纳米管（BNNT）上的金纳米晶体进行了原位电子束辐照研究。通过一种精确控制的溅射方法制备了尺寸为2⁻4纳米的金纳米晶体颗粒，使其在BNNT表面自由站立，不存在化学键相互作用。金纳米颗粒在连续电子束辐照下呈现出表面原子无序、扩散现象，进一步还有主要包含充电、活化和邻接三个阶段的长程运动，随后是最终的晶体生长。首先，生长过程经历晶格扩散，随后是表面主导的扩散机制。这些与经典情况和先前报道根本不同的异常现象和观察结果，主要是由于金纳米颗粒的过充电，在高能等离子体方面产生了表面活化状态。因此，这项工作为单纳米晶体和双纳米晶体系统带来了新的观察结果，以及在理解由此产生的动力学行为方面的新见解。
