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Title: In situ liquid cell TEM reveals bridge-induced contact and fusion of Au nanocrystals in aqueous solution

Abstract

During nanoparticle coalescence in aqueous solution, dehydration and initial contact of particles are critically important but poorly understood processes. In this work, we used in situ liquid-cell transmission electron microscopy to directly visualize the coalescence process of Au nanocrystals. It was found that the Au atomic nanobridge forms between adjacent nanocrystals that are separated by a ~0.5 nm hydration layer. The nanobridge structure first induces initial contact of Au nanocrystals over their hydration layers and then surface diffusion and grain boundary migration to rearrange into a single nanocrystal. Classical density functional theory calculations and ab initio molecular dynamics simulations suggest that the formation of the nanobridge can be attributed to the accumulation of auric ions and a higher local supersaturation in the gap, which can promote dehydration, contact, and fusion of Au nanocrystals. The discovery of this multistep process advances our understanding of the nanoparticle coalescence mechanism in aqueous solutions.

Authors:
 [1]; ORCiD logo [2];  [1];  [1];  [1]
  1. Zhejiang University
  2. BATTELLE (PACIFIC NW LAB)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1558425
Report Number(s):
PNNL-SA-139589
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 18; Journal Issue: 10
Country of Publication:
United States
Language:
English

Citation Formats

Jin, Biao, Sushko, Maria L., Jin, Chuanhong, Liu, Zhaoming, and Tang, Ruikang. In situ liquid cell TEM reveals bridge-induced contact and fusion of Au nanocrystals in aqueous solution. United States: N. p., 2018. Web. doi:10.1021/acs.nanolett.8b03139.
Jin, Biao, Sushko, Maria L., Jin, Chuanhong, Liu, Zhaoming, & Tang, Ruikang. In situ liquid cell TEM reveals bridge-induced contact and fusion of Au nanocrystals in aqueous solution. United States. doi:10.1021/acs.nanolett.8b03139.
Jin, Biao, Sushko, Maria L., Jin, Chuanhong, Liu, Zhaoming, and Tang, Ruikang. Wed . "In situ liquid cell TEM reveals bridge-induced contact and fusion of Au nanocrystals in aqueous solution". United States. doi:10.1021/acs.nanolett.8b03139.
@article{osti_1558425,
title = {In situ liquid cell TEM reveals bridge-induced contact and fusion of Au nanocrystals in aqueous solution},
author = {Jin, Biao and Sushko, Maria L. and Jin, Chuanhong and Liu, Zhaoming and Tang, Ruikang},
abstractNote = {During nanoparticle coalescence in aqueous solution, dehydration and initial contact of particles are critically important but poorly understood processes. In this work, we used in situ liquid-cell transmission electron microscopy to directly visualize the coalescence process of Au nanocrystals. It was found that the Au atomic nanobridge forms between adjacent nanocrystals that are separated by a ~0.5 nm hydration layer. The nanobridge structure first induces initial contact of Au nanocrystals over their hydration layers and then surface diffusion and grain boundary migration to rearrange into a single nanocrystal. Classical density functional theory calculations and ab initio molecular dynamics simulations suggest that the formation of the nanobridge can be attributed to the accumulation of auric ions and a higher local supersaturation in the gap, which can promote dehydration, contact, and fusion of Au nanocrystals. The discovery of this multistep process advances our understanding of the nanoparticle coalescence mechanism in aqueous solutions.},
doi = {10.1021/acs.nanolett.8b03139},
journal = {Nano Letters},
number = 10,
volume = 18,
place = {United States},
year = {2018},
month = {10}
}