Ag Nanotwin-Assisted Grain Growth-Induced by Stress in SiO₂/Ag/SiO₂ Nanocap Arrays.

Fan Zhang,Yongjun Zhang,Yaxin Wang,Ling Yang ,Hua Zhong ,Jing Yang

doi:10.3390/nano8060436

Abstract

A trilayer SiO2/Ag/SiO2 nanocap array was prepared on a two-dimensional template. When annealed at different temperatures, the curvature of the SiO2/Ag/SiO2 nanocap arrays increased, which led to Ag nanocap shrinkage. The stress provided by the curved SiO2 layer induced the formation of Ag nanotwins. Ag nanotwins assisted the growth of nanoparticles when the neighboring nanotwins changed the local misorientations. Nanocap shrinkage reduced the surface plasmon resonance (SPR) coupling between neighboring nanocaps; concurrently, grain growth decreased the SPR coupling between the particles in each nanocap, which led to a red shift of the localized surface plasmon resonance (LSPR) bands and decreased the surface-enhanced Raman scattering (SERS) signals.

Highlights

Nanotwins, the plastic deformations of nanostructured materials, are widely reported among the face-centered cubic metals [1,2,3]
Molecular dynamics (MD) simulation and experimental observations have revealed the relationship of nanotwins to the motion and dissociation of grain boundaries (GBs) [12]
The performance characterization methods used in the experiment predominantly included the scanning electron microscope (SEM), transmission electron microscope (TEM), UV-Vis spectra with a Shimadzu UV-3600 spectrophotometer (Shimadzu, Kyoto, Japan), and X-ray powder diffraction (XRD)

Summary

Introduction

The plastic deformations of nanostructured materials, are widely reported among the face-centered cubic (fcc) metals [1,2,3]. Molecular dynamics (MD) simulation and experimental observations have revealed the relationship of nanotwins to the motion and dissociation of grain boundaries (GBs) [12]. In addition to mechanically induced stress, stress in the curved nanostructures was observed, which led to the typical evolution of the physical properties [19]. This type of stress can be adjusted by the curvature and the film thickness. By controlling the annealing temperature, the curvature of the SiO2/Ag/SiO2 nanocap arrays as well as the stress increased. Stress induced the grain rotation and formation of Ag nanotwins in SiO2/Ag/SiO2 nanocap arrays when annealed. The morphology and microstructure changes led to changes in the surface plasmon

Materials

Preparation of PS Colloidal Sphere Arrays

Characterization of Substrates

Findings

Conclusions