Advanced electron microscopy of local atomic displacements depending on the outer shape in gold nanorods

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01830
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28030:Nanomaterials-related
• Research Institution: Kyushu University
• Principal Investigator: Matsumura Syo 九州大学, 工学研究院, 教授 (60150520)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 高分解能電子顕微鏡 / ナノ粒子 / 原子変位 / 格子歪 / プラズモニクス / レーザー光照射

Outline of Final Research Achievements

Advanced atomic-resolution electron microscopy including Gaussian process regression for statistical noise reduction has disclosed quantitatively local strain inherent in gold nanoparticles depending on the shape with an improved accuracy about 0.2 %. Rod-shaped nanoparticles involve characteristic expansion strain ~+1.0 % along the long axis within capped tip portions, in addition to surface contraction skin generally existing in nanoparticles. The shape depending inherent local strain has been evidenced by molecular dynamics simulations, and has been attributed to curvature-dependent surface contraction stress. The present results bring hints to nanoscale engineering to optimize the interior strain in nanoparticles by shape control. In addition, the structural and shape transformation of gold nanorods under near-infrared laser illumination has been explained well experimentally in terms of abrupt heating due to the absorbed energy.

Free Research Field

ナノ材料物性

Academic Significance and Societal Importance of the Research Achievements

金属ナノ粒子の内部に局所的に不均質な格子歪みが発生することを実験的に明らかにし、それが粒子表面の局所的な曲率とその変化で理解できることを示したことは、様々な機能素子としての応用が期待されている金属ナノ粒子の機能を格子歪みによって制御する可能性を拓くことに繋がる。さらにレーザー光照射による構造相転移の基本的な機構も明らかになり、光照射による金属ナノ粒子の状態と機能制御の可能性も示した。