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@INPROCEEDINGS{Sun:1021027,
author = {Sun, H. and Park, Junbeom and Basak, Shibabrata and Beker,
A. and van Omme, J. T. and Pivak, Y. and Garza, H. H. P.},
title = {{H}igh resolution and analytical transmission electron
microscopy in a liquid flow cell via gas purging},
reportid = {FZJ-2024-00487},
year = {2023},
abstract = {Liquid phase electron microscopy (LPEM) based on sandwiched
MEMS sample carriers provides the means toobserve
time-resolved dynamics in a liquid state. Until now, LPEM
has been widely used in materials science,energy and life
science, providing fundamental insights into nucleation and
growth, the dynamical evolution ofkey materials in batteries
and fuel cells, as well as the 3D imaging of biomolecules
[1]. Compared to liquid cellswithout a flowing function
(such as static graphene pocket cells), liquid flow cells
have obvious advantages.This includes the control of the
liquid environment, the modulation of the effect of electron
beam irradiation [2]and the integration of functional
electrodes for heating or/and biasing. Due to the pressure
difference betweenthe TEM column (~ 0 bar) and the enclosed
liquid cell (~1 bar), the two membranes (silicon nitride
with atypical thickness of ~50 nm) bulge outwards, resulting
in a thick liquid layer, which can reach more than
1micrometer in the cell center region. Therefore, performing
high resolution and analytical electron microscopystudies in
a liquid flow cell comes with a multitude of
challenges.Several strategies have been proposed to solve
this issue, including (1) decreasing the membrane thickness
orreplacing it with ultrathin materials e.g. graphene, h-BN,
MoS2, etc. [3], (2) developing novel cellconfigurations,
namely hole array patterns [4] and nanochannel [5], to avoid
or decrease the bulging, (3)generating a gas bubble via
electron beam irradiation [6,7], (4) generating a gas bubble
via electrochemicalwater splitting [8] and (5) mitigating
the window´s bulging by changing the pressure difference
between the celland TEM column, either via an external
pressure controller [9,10] or via the internal Laplace
pressure [10].Those methods have been proven useful in high
resolution and analytical electron microscopy studies in
LPEM,however, there are also intrinsic limitations in each
method.In this work, we propose a general and robust method
to perform high resolution and analytical electronmicroscopy
studies in a flow cell (the Stream Nano-Cell), which can be
implemented during liquid heating orliquid biasing
experiments. Thanks to the on-chip flow channel of the
Stream Nano-Cell [11], the liquid in thefield of view can be
removed by flowing gas (including inert gases to avoid
problems with air sensitivity), whichis termed "purging".
This purging method enables the acquisition of
high-resolution TEM images, chemicalcomposition and valence
analysis through energy-dispersive X-ray spectroscopy (EDX)
mapping and ElectronEnergy-Loss Spectroscopy (EELS),
respectively. In addition, the purging approach is both
reversible andreproducible, which therefore enables the
alternation between a full cell and a thin liquid
configuration to studyliquid-thickness-dependent physical
and chemical phenomena.References1.F. M. Ross. Science,
2015, 350, aaa9886.2.N. M. Schneider, et al. J. Phys. Chem.
C, 2014, 118, 22373.3.G. Dunn, et al., ACS Nano, 2020, 14,
9637.4.S. Nagashima, et al. Nano Lett., 2019, 19, 10,
7000.5.M. N. Yesibolati, et al. Phys. Rev. Lett., 2020, 124,
065502.6.G. Zhu, et al. Chem. Commun. 2013, 49, 10944.7.U.
Mirsaidov, et al. Soft Matter, 2012, 8, 7108.8.R.
Serra-Maia, et al. ACS Nano 2021, 15, 10228.9.S. Keskin, et
al. Nano Lett., 2019, 19, 4608.10.H. Wu, et al. Small
Methods, 2021, 5, 2001287.11.A. F. Beker, et al. Nanoscale,
2020, 12, 22192.},
month = {Feb},
date = {2023-02-26},
organization = {Microscopy Conference 2023, Darmstadt
(Germany), 26 Feb 2023 - 2 Mar 2023},
subtyp = {After Call},
cin = {IEK-9},
cid = {I:(DE-Juel1)IEK-9-20110218},
pnm = {1232 - Power-based Fuels and Chemicals (POF4-123)},
pid = {G:(DE-HGF)POF4-1232},
typ = {PUB:(DE-HGF)24},
url = {https://juser.fz-juelich.de/record/1021027},
}