skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


This content will become publicly available on March 18, 2026

Title: Radiation Chemistry in Environmental Transmission Electron Microscopy
Environmental transmission electron microscopy (E-TEM) enables direct observation of nanoscale chemical processes crucial for catalysis and materials design. However, the high-energy electron probe can dramatically alter reaction pathways through radiolysis, the dissociation of molecules under electron beam irradiation. While extensively studied in liquid-cell TEM, the impact of radiolysis in gas phase reactions remains unexplored. Here, we present a numerical model elucidating radiation chemistry in both gas and liquid E-TEM environments. Our findings reveal that while gas phase E-TEM generates radiolytic species with lower reactivity than liquid phase systems, these species can accumulate to reaction-altering concentrations, particularly at elevated pressures. We validate our model through two case studies: the radiation-promoted oxidation of aluminum nanocubes and disproportionation of carbon monoxide. In both cases, increasing the electron beam dose rate directly accelerates their reaction kinetics, as demonstrated by enhanced AlOx growth and carbon deposition. Based on these insights, we establish practical guidelines for controlling radiolysis in closed-cell nanoreactors. This work not only resolves a fundamental challenge in electron microscopy but also advances our ability to rationally design materials with subÅngstrom resolution.  more » « less
Award ID(s):
2437819 2025633
PAR ID:
10640021
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
ACS NANO
Date Published:
Journal Name:
ACS Nano
Volume:
19
Issue:
10
ISSN:
1936-0851
Page Range / eLocation ID:
10369 to 10380
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, MRS Bulletin)
    null (Ed.)
    This article addresses recent advances in liquid phase transmission electron microscopy (LPTEM) for studying nanoscale synthetic processes of carbon-based materials that are independent of the electron beam—those driven by nonradiolytic chemical or thermal reactions. In particular, we focus on chemical/physical formations and the assembly of nanostructures composed of organic monomers/polymers, peptides/DNA, and biominerals. The synthesis of carbon-based nanomaterials generally only occurs at specific conditions, which cannot be mimicked by aqueous solution radiolysis. Carbon-based structures themselves are also acutely sensitive to the damaging effects of the irradiating beam, which make studying their synthesis using LPTEM a unique challenge that is possible when beam effects can be quantified and mitigated. With new direct sensing, high frame-rate cameras, and advances in liquid cell holder designs, combined with a growing understanding of irradiation effects and proper experimental controls, microscopists have been able to make strides in observing traditionally problematic carbon-based materials under conditions where synthesis can be controlled, and imaged free from beam effects, or with beam effects quantified and accounted for. These materials systems and LPTEM experimental techniques are discussed, focusing on nonradiolytic chemical and physical transformations relevant to materials synthesis. 
    more » « less
  2. ; ; ; (, Small Methods)
    Abstract Imaging materials and biological structures in a liquid environment pose a significant challenge for conventional transmission electron microscopy (TEM) due to stringent requirement of ultrahigh vacuum design in the microscope column. The most recent liquid‐cell TEM technique, graphene liquid‐cell (GLC) microscopy, employs only layers of graphene to encapsulate liquid specimens. Recent efforts with GLC–TEM have demonstrated superior imaging resolution of beam‐sensitive specimens. Herein, the parameters that affect the quality of GLC analysis, including the graphene transfer onto TEM grids, are reviewed. Several important factors that affect the in situ TEM imaging of specimens, including the variations in GLC geometries and capillary pressure are discussed. The interaction between the electron beam and the liquid along with the possibility for artifacts or the formation of radical ions is also highlighted in this review. The scientific discoveries enabled by GLC–TEM in the areas of nucleation and growth of crystals, corrosion, battery science, as well as high‐resolution imaging of organelles and proteins are also briefly discussed. Finally, possible future research directions of GLC–TEM and the associated challenges are discussed. The synergistic effort to accomplish the proposed research directions has the potential to yield new discoveries in both materials and life sciences. 
    more » « less
  3. ; (, MRS Bulletin)
    Abstract Detailed studies of interfacial gas-phase chemical reactions are important for understanding factors that control materials synthesis and environmental conditions that govern materials performance and degradation. Out of the many materials characterization methods that are available for interpreting gas–solid reaction processes,in situandoperandotransmission electron microscopy (TEM) is perhaps the most versatile, multimodal materials characterization technique. It has successfully been utilized to study interfacial gas–solid interactions under a wide range of environmental conditions, such as gas composition, humidity, pressure, and temperature. This stems from decades of R&D that permit controlled gas delivery and the ability to maintain a gaseous environment directly within the TEM column itself or through specialized side-entry gas-cell holders. Combined with capabilities for real-time, high spatial resolution imaging, electron diffraction and spectroscopy, dynamic structural and chemical changes can be investigated to determine fundamental reaction mechanisms and kinetics that occur at site-specific interfaces. This issue ofMRS Bulletincovers research in this field ranging from technique development to the utilization of gas-phase microscopy methods that have been used to develop an improved understanding of multilength-scaled processes incurred during materials synthesis, catalytic reactions, and environmental exposure effects on materials properties. Graphical abstract 
    more » « less
  4. ; ; ; ; ; ; (, Microscopy and Microanalysis)
    Abstract This work describes cryogenic ex situ lift out (cryo-EXLO) of cryogenic focused ion beam (cryo-FIB) thinned specimens for analysis by cryogenic transmission electron microscopy (cryo-TEM). The steps and apparatus necessary for cryo-EXLO are described. Methods designed to limit ice contamination include use of an anti-frost lid, a vacuum transfer assembly, and a cryostat. Cryo-EXLO is performed in a cryostat with the cryo-shuttle holder positioned in the cryogenic vapor phase above the surface of liquid N2 (LN2) using an EXLO manipulation station installed inside a glove box maintained at < 10% relative humidity and inert (e.g., N2 gas) conditions. Thermal modeling shows that a cryo-EXLO specimen will remain vitreous within its FIB trench indefinitely while LN2 is continuously supplied. Once the LN2 is cut off, modeling shows that the EXLO specimen will remain vitreous for over 4 min, allowing sufficient time for the cryo-transfer steps which take only seconds to perform. Cryo-EXLO was applied successfully to cryo-FIB-milled specimen preparation of a polymer sample and plunge-frozen yeast cells. Cryo-TEM of both the polymer and the yeast shows minimal ice contamination with the yeast specimen maintaining its vitreous phase, illustrating the potential of cryo-EXLO for cryo-FIB-TEM of beam-sensitive, liquid, or biological materials. 
    more » « less
  5. ; ; ; (, Microscopy and Microanalysis)
    Electron beam-induced polymerization (EBIP) has been widely explored in coatings, adhesives, and nanostructure fabrication, relying on electron irradiation to generate reactive species that initiate polymerization via radical pathways [1]. While its efficiency in solid and thin-film systems is well established [2], real-time observation of gas-phase polymerization at the nanoscale remains challenging due to the lack of suitable experimental platforms. In this study, we employ a custom-built ultrathin (UT) membrane gas-cell chip for in-situ closed-cell environmental transmission electron microscopy (ETEM). This platform offers enhanced reciprocal and spectral visibility, enabling precise tracking of crystallinity through diffraction patterns and gas composition through electron energy loss spectroscopy (EELS) [3-5]. By allowing real-time observation of polymerization kinetics under controlled electron irradiation, this work aims to elucidate the fundamental mechanisms governing EBIP in the gas phase, addressing a critical knowledge gap in electron beam-driven chemical reactions. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email