Title: Temperature-Driven Transformation of CsPbBr ₃ Nanoplatelets into Mosaic Nanotiles in Solution through Self-Assembly

Abstract

Two-dimensional colloidal halide perovskite nanocrystals are promising materials for light-emitting applications. Recent studies have focused on nanoplatelets that are able to selfassemble and transform on solid substrates. However, the mechanism behind the process and the atomic arrangement of their assemblies remain unclear. Here, we present a detailed analysis of the transformation of self-assembled stacks of CsPbBr₃ nanoplatelets in solution over a period of a few months by using ex situ transmission electron microscopy and surface analysis. We demonstrate that the transformation mechanism can be understood as oriented attachment, proceeding through the following steps: (i) desorption of the ligands from the surfaces of the particles, causing the seamless atomic merging of nanoplatelet stacks into nanobelts; (ii) merging of neighboring nanobelts that form more extended nanoplates; and (iii) attachment of nanobelts and nanoplates, forming objects with an atomic structure that resembles a mosaic made of broken nanotiles. We reveal that aged nanobelts and nanoplates, which are mainly stabilized by amine/ammonium ions, link through a bilayer of CsBr, with the atomic columns of neighboring perovskite lattices shifted by a half-unit-cell, forming Ruddlesden-Popper planar faults. We also show, via in situ monitoring of the nanocrystal photoluminescence combined with transmission electron microscopy analysis, that themore » transformation is temperature driven and that it can take place within tens of minutes in solution and in spin-coated films. Understanding this process gives crucial information for the design and fabrication of perovskite materials, where control over the type and density of defects is desired, stimulating the development of perovskite nanocrystal structures with tailored electronic properties.« less

Authors:

Dang, Zhiya ;

• Search DOE PAGES for author "Dang, Zhiya"
• Search DOE PAGES for ORCID "0000-0003-2238-540X"

Dhanabalan, Balaji ^[1]; Castelli, Andrea; Dhall, Rohan ^[2]; Bustillo, Karen C. ^[2]; Marchelli, Dorwal; Spirito, Davide; Petralanda, Urko; Shamsi, Javad ;

• Search DOE PAGES for author "Shamsi, Javad"
• Search DOE PAGES for ORCID "0000-0003-4684-5407"

Manna, Liberato ;

• Search DOE PAGES for author "Manna, Liberato"
• Search DOE PAGES for ORCID "0000-0003-4386-7985"

Krahne, Roman; Arciniegas, Milena P.

• Search DOE PAGES for author "Arciniegas, Milena P."
• Search DOE PAGES for ORCID "0000-0002-7454-8891"

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+ Show Author Affiliations

1. Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso, 31, 16146 Genova, Italy
2. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States

Publication Date:

Tue Jan 28 00:00:00 EST 2020

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division

OSTI Identifier:

1766592

Alternate Identifier(s):

OSTI ID: 1815738

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Nano Letters

Additional Journal Information:

Journal Name: Nano Letters Journal Volume: 20 Journal Issue: 3; Journal ID: ISSN 1530-6984

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; CsPbBr₃; perovskite; nanoplatelets; self-assembly; transformations; temperature; transmission electron microscopy