Mapping short-range order at the nanoscale in metal-organic framework and inorganic glass composites
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Characterization of nanoscale changes in the atomic structure of amorphous materials is a profound challenge. Established X-ray and neutron total scattering methods typically provide sufficient signal quality only over macroscopic volumes. Pair distribution function analysis using electron scattering (ePDF) in the scanning transmission electron microscope (STEM) has emerged as a method of probing nanovolumes of these materials, but inorganic glasses as well as metal–organic frameworks (MOFs) and many other materials containing organic components are characteristically prone to irreversible changes after limited electron beam exposures. This beam sensitivity requires ‘low-dose’ data acquisition to probe inorganic glasses, amorphous and glassy MOFs, and MOF composites. Here, we use STEM-ePDF applied at low electron fluences (10 e− Å−2) combined with unsupervised machine learning methods to map changes in the short-range order with ca. 5 nm spatial resolution in a composite material consisting of a zeolitic imidazolate framework glass agZIF-62 and a 0.67([Na2O]0.9[P2O5])–0.33([AlO3/2][AlF3]1.5) inorganic glass. STEM-ePDF enables separation of MOF and inorganic glass domains from atomic structure differences alone, showing abrupt changes in atomic structure at interfaces with interatomic correlation distances seen in X-ray PDF preserved at the nanoscale. These findings underline that the average bulk amorphous structure is retained at the nanoscale in the growing family of MOF glasses and composites, a previously untested assumption in PDF analyses crucial for future non-crystalline nanostructure engineering.
Date Issued
2022-11-28
Date Acceptance
2022-10-20
Citation
Nanoscale, 2022, 14 (44), pp.16524-16535
ISSN
2040-3364
Publisher
Royal Society of Chemistry
Start Page
16524
End Page
16535
Journal / Book Title
Nanoscale
Volume
14
Issue
44
Copyright Statement
This journal is © The Royal Society of Chemistry 2022. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/36285652
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2022-10-21