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Title: In situ TEM observation of neck formation during oriented attachment of PbSe nanocrystals

Abstract

Oriented attachment of nanocrystals is an important route to constructing epitaxially-connected nanocrystal superlattices for various applications. During oriented attachment of semiconductor nanocrystals, neck can be formed between nanocrystals and it strongly influences the properties of the resulting superlattice. However, the neck formation mechanism is poorly understood. Here, we use in situ liquid cell transmission electron microscopy to directly observe the initiation and growth of homoepitaxial necks between PbSe nanocrystals with atomic details. We find that neck initiation occurs slowly (~ 10 s) when two nanocrystals approach to each other within an edge-to-edge distance of 0.6 nm. During neck initiation, Pb and Se atoms defuse from other facets into the gap, forming “dynamic reversible” filaments. Once the filament (neck) width is larger than a critical size of 0.9 nm, it gradually (15 s) widens into a 3-nm-wide neck. The atomic structure of the neck is further obtained using ex situ aberration-corrected scanning TEM imaging. Neck initiation and growth mechanisms are elucidated with density functional theory calculations. As a result, our direct unveiling of the atomic pathways of neck formation during oriented attachment shed light into the fabrication of nanocrystal superlattices with improved structural order and electronic properties.

Authors:
 [1];  [2];  [3];  [4];  [3];  [4];  [4];  [3];  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xiamen Univ., Xiamen (China)
  3. Univ. of California, Irvine, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
OSTI Identifier:
1563993
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Nano Research
Additional Journal Information:
Journal Volume: 12; Journal Issue: 10; Journal ID: ISSN 1998-0124
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
PbSe nanocrystals; quantum dots; superlattices; necking; oriented attachment; liquid cell transmission electron microscopy (TEM)

Citation Formats

Wang, Yu, Peng, Xinxing, Abelson, Alex, Zhang, Bing-Kai, Qian, Caroline, Ercius, Peter, Wang, Lin-Wang, Law, Matt, and Zheng, Haimei. In situ TEM observation of neck formation during oriented attachment of PbSe nanocrystals. United States: N. p., 2019. Web. doi:10.1007/s12274-019-2483-8.
Wang, Yu, Peng, Xinxing, Abelson, Alex, Zhang, Bing-Kai, Qian, Caroline, Ercius, Peter, Wang, Lin-Wang, Law, Matt, & Zheng, Haimei. In situ TEM observation of neck formation during oriented attachment of PbSe nanocrystals. United States. doi:10.1007/s12274-019-2483-8.
Wang, Yu, Peng, Xinxing, Abelson, Alex, Zhang, Bing-Kai, Qian, Caroline, Ercius, Peter, Wang, Lin-Wang, Law, Matt, and Zheng, Haimei. Mon . "In situ TEM observation of neck formation during oriented attachment of PbSe nanocrystals". United States. doi:10.1007/s12274-019-2483-8.
@article{osti_1563993,
title = {In situ TEM observation of neck formation during oriented attachment of PbSe nanocrystals},
author = {Wang, Yu and Peng, Xinxing and Abelson, Alex and Zhang, Bing-Kai and Qian, Caroline and Ercius, Peter and Wang, Lin-Wang and Law, Matt and Zheng, Haimei},
abstractNote = {Oriented attachment of nanocrystals is an important route to constructing epitaxially-connected nanocrystal superlattices for various applications. During oriented attachment of semiconductor nanocrystals, neck can be formed between nanocrystals and it strongly influences the properties of the resulting superlattice. However, the neck formation mechanism is poorly understood. Here, we use in situ liquid cell transmission electron microscopy to directly observe the initiation and growth of homoepitaxial necks between PbSe nanocrystals with atomic details. We find that neck initiation occurs slowly (~ 10 s) when two nanocrystals approach to each other within an edge-to-edge distance of 0.6 nm. During neck initiation, Pb and Se atoms defuse from other facets into the gap, forming “dynamic reversible” filaments. Once the filament (neck) width is larger than a critical size of 0.9 nm, it gradually (15 s) widens into a 3-nm-wide neck. The atomic structure of the neck is further obtained using ex situ aberration-corrected scanning TEM imaging. Neck initiation and growth mechanisms are elucidated with density functional theory calculations. As a result, our direct unveiling of the atomic pathways of neck formation during oriented attachment shed light into the fabrication of nanocrystal superlattices with improved structural order and electronic properties.},
doi = {10.1007/s12274-019-2483-8},
journal = {Nano Research},
number = 10,
volume = 12,
place = {United States},
year = {2019},
month = {7}
}

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Works referenced in this record:

Prospects for thermoelectricity in quantum dot hybrid arrays
journal, December 2015


Ligand Exchange and the Stoichiometry of Metal Chalcogenide Nanocrystals: Spectroscopic Observation of Facile Metal-Carboxylate Displacement and Binding
journal, November 2013

  • Anderson, Nicholas C.; Hendricks, Mark P.; Choi, Joshua J.
  • Journal of the American Chemical Society, Vol. 135, Issue 49, p. 18536-18548
  • DOI: 10.1021/ja4086758