Lattice Tetragonality and Local Strain Depending on Shape of Gold Nanoparticles
Lattice Tetragonality and Local Strain Depending on Shape of Gold Nanoparticles
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DOI：
10.1017/s1431927619011346
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发表时间：
2019-08
影响因子：
2.8
通讯作者：
K. Aso;J. Maebe;Tomokazu Yamamoto;S. Matsumura
中科院分区：
文献类型：
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作者：
K. Aso;J. Maebe;Tomokazu Yamamoto;S. Matsumura
金属纳米粒子引起了许多研究兴趣并应用于各种功能材料，例如光学器件、催化剂等。众所周知，纳米粒子中的晶格应变通过电子态的局部变化影响功能特性[1]。了解引起纳米颗粒局部应变的基本机制非常重要。本研究旨在通过HAADFYSTEM原子分辨率观测系统地分析金纳米棒中局部晶格应变与长宽比的函数关系。金纳米棒的原子分辨率HAADFYSTEM观测是使用JEMY ARM200CF在120 NV的加速电压下进行的。在快速探针扫描（1.0 μsec/像素）下获得纳米棒的多个 HAADFYSTEM 图像，以抑制由于样本漂移导致的图像失真，并将它们叠加以提高图像的信噪比。图1显示了沿[ͳതͳͲ]晶体方向观察到的单晶金纳米粒子的原子分辨率HAADF图像。纳米颗粒的[001]和[110]方向分别设置为图像的横向x和纵向y。我们观察到三个纳米粒子，其宽度几乎与a9相同。 0 nm，但长度或纵横比（AR）不同，例如1.0（图1a）、2.1（图1b）和3.6。以下分别将它们称为NP1、NP2和NP3。
Metal nanoparticles have attracted many research interests and are applied to various functional materials, such as optical devices, catalysts and so on. It is well Nnown that lattice strain in nanoparticles affects the functional properties through local variation in the electron state [1]. It is quite important to understand basic mechanisms to cause the local strain in nanoparticles. The present study was aimed to analyse systematically the local lattice strains in gold nanorods as a function of the aspect ratio by HAADFYSTEM atomic resolution observations.Atomic resolution HAADFYSTEM observations of gold nanorods were carried out using a JEMY ARM200CF at an acceleration voltage of 120 NV. Plural HAADFYSTEM images of a nanorod were obtained under fast probe scanning (1.0 μsec/pixel) to suppress the image distortion due to specimen drift and they were superimposed to improve the S/N ratios of the images. Figure 1 shows atomic resolution HAADF images of singleYcrystalline gold nanoparticles observed along [ͳതͳͲ] crystal direction. The [001] and [110] directions of the nanoparticles are set to the lateral direction x and the longitudinal direction y of the images, respectively. We observed three nanoparticles which were the almost same in width as a9. 0 nm but were different in length, or in the aspect ratio (AR) such as 1.0 (Fig. 1a), 2.1 (Fig. 1b) and 3.6. Hereinafter they are referred to as NP1, NP2 and NP3, respectively.