TY - JOUR
T1 - Subpercent Local Strains Due to the Shapes of Gold Nanorods Revealed by Data-Driven Analysis
AU - Aso, Kohei
AU - Maebe, Jens
AU - Tran, Xuan Quy
AU - Yamamoto, Tomokazu
AU - Oshima, Yoshifumi
AU - Matsumura, Syo
N1 - Funding Information:
The authors are grateful to Assoc. Prof. Yukio Sato at Kyushu University for a discussion regarding image distortion correction and Dr. Masaki Kudo and Mr. Takaaki Toriyama at the Ultramicroscopy Research Center for technical support. This work was partly financially supported by Grant-in-Aid for Scientific Research B (No. 25289221 and No. 18H01830) from Japan Society for the Promotion of Science, the ACCEL program (JPMJAC1501), Japan Science and Technology Agency (JST), and Education and Research Support Program on Mathematics and Data Science 2017 from Kyushu University.
Publisher Copyright:
© 2021 The Authors. Published by American Chemical Society.
PY - 2021/7/27
Y1 - 2021/7/27
N2 - Analysis of subpercent local strain is important for a deeper understanding of nanomaterials, whose properties often depend on the strain. Conventional strain analysis has been performed by measuring interatomic distances from scanning transmission electron microscopy (STEM) images. However, measuring subpercent strain remains a challenge because the peak positions in STEM images do not precisely correspond to the real atomic positions due to disturbing influences, such as random noise and image distortion. Here, we utilized an advanced data-driven analysis method, Gaussian process regression, to predict the true strain distribution by reconstructing the true atomic positions. As a result, a precision of 0.2% was achieved in strain measurement at the atomic scale. The method was applied to gold nanoparticles of different shapes to reveal the shape dependence of the strain distribution. A spherical gold nanoparticle showed a symmetric strain distribution with a contraction of ∼1% near the surface owing to surface relaxation. By contrast, a gold nanorod, which is a cylinder terminated by hemispherical caps on both sides, showed nonuniform strain distributions with lattice expansions of ∼0.5% along the longitudinal axis around the caps except for the contraction at the surface. Our results indicate that the strain distribution depends on the shape of the nanomaterials. The proposed data-driven analysis is a convenient and powerful tool to measure the strain distribution with high precision at the atomic scale.
AB - Analysis of subpercent local strain is important for a deeper understanding of nanomaterials, whose properties often depend on the strain. Conventional strain analysis has been performed by measuring interatomic distances from scanning transmission electron microscopy (STEM) images. However, measuring subpercent strain remains a challenge because the peak positions in STEM images do not precisely correspond to the real atomic positions due to disturbing influences, such as random noise and image distortion. Here, we utilized an advanced data-driven analysis method, Gaussian process regression, to predict the true strain distribution by reconstructing the true atomic positions. As a result, a precision of 0.2% was achieved in strain measurement at the atomic scale. The method was applied to gold nanoparticles of different shapes to reveal the shape dependence of the strain distribution. A spherical gold nanoparticle showed a symmetric strain distribution with a contraction of ∼1% near the surface owing to surface relaxation. By contrast, a gold nanorod, which is a cylinder terminated by hemispherical caps on both sides, showed nonuniform strain distributions with lattice expansions of ∼0.5% along the longitudinal axis around the caps except for the contraction at the surface. Our results indicate that the strain distribution depends on the shape of the nanomaterials. The proposed data-driven analysis is a convenient and powerful tool to measure the strain distribution with high precision at the atomic scale.
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U2 - 10.1021/acsnano.1c03413
DO - 10.1021/acsnano.1c03413
M3 - Article
C2 - 34232021
AN - SCOPUS:85111227921
VL - 15
SP - 12077
EP - 12085
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 7
ER -