Room-Temperature Magnetoelectric Coupling in Electronic Ferroelectric Film based on [(n-C3H7)4N][FeIIIFeII(dto)3] (dto = C2O2S2)

Article abstract of DOI:10.1021/jacs.1c00601

Great importance has been attached to magnetoelectric coupling in multiferroic thin films owing to their extremely practical use in a new generation of devices. Here, a film of [(n-C3H7)4N][FeIIIFeII(dto)3] (1; dto = C2O2S2) was fabricated using a simple stamping process. As was revealed by our experimental results, in-plane ferroelectricity over a wide temperature range from 50 to 300 K was induced by electron hopping between FeII and FeIII sites. This mechanism was further confirmed by the ferroelectric observation of the compound [(n-C3H7)4N][FeIIIZnII(dto)3] (2; dto = C2O2S2), in which FeII ions were replaced by nonmagnetic metal ZnII ions, resulting in no obvious ferroelectric polarization. However, both ferroelectricity and magnetism are related to the magnetic Fe ions, implying a strong magnetoelectric coupling in 1. Through piezoresponse force microscopy (PFM), the observation of magnetoelectric coupling was achieved by manipulating ferroelectric domains under an in-plane magnetic field. The present work not only provides new insight into the design of molecular-based electronic ferroelectric/magnetoelectric materials but also paves the way for practical applications in a new generation of electronic devices.

Full text of DOI:10.1021/jacs.1c00601

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Article
Room-Temperature Magnetoelectric Coupling in Electronic
Ferroelectric Film based on [(n‑C3H7)4N][FeIIIFeII(dto)3] (dto = C2O2S2)
Xiaolin Liu,§ Bin Wang,§ Xiaofeng Huang, Xinwei Dong,* Yanping Ren, Haixia Zhao,* Lasheng Long,*
and Lansun Zheng
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ABSTRACT: Great importance has been attached to magnetoelectric coupling in
multiferroic thin films owing to their extremely practical use in a new generation of
devices. Here, a film of [(n-C3H7)4N][FeIIIFeII(dto)3] (1; dto = C2O2S2) was fabricated
using a simple stamping process. As was revealed by our experimental results, in-plane
ferroelectricity over a wide temperature range from 50 to 300 K was induced by electron
hopping between FeII and FeIII sites. This mechanism was further confirmed by the
ferroelectric observation of the compound [(n-C3H7)4N][FeIIIZnII(dto)3] (2; dto =
C2O2S2), in which FeII ions were replaced by nonmagnetic metal ZnII ions, resulting in no
obvious ferroelectric polarization. However, both ferroelectricity and magnetism are related
to the magnetic Fe ions, implying a strong magnetoelectric coupling in 1. Through
piezoresponse force microscopy (PFM), the observation of magnetoelectric coupling was
achieved by manipulating ferroelectric domains under an in-plane magnetic field. The
present work not only provides new insight into the design of molecular-based electronic
ferroelectric/magnetoelectric materials but also paves the way for practical applications in a new generation of electronic devices.
MEs.23,25 However, subsequent studies showed that only a
INTRODUCTION
■
small number of inorganic oxides have been confirmed as CO
Recently, magnetoelectric effects (MEs) in multiferroic
materials have attracted considerable attention due to their
multiferroics that show MEs.26
In contrast, investigations on CO multiferroics have been
extensive practical applications as information memory, new
extended to molecular-based compounds in recent years,27−29
due to the outstanding advantages of molecular-based
compounds, such as diversity and adjustable structure, mild
synthesis conditions, and ease of processing.30−32 Actually,
among the molecular-based compounds, the intra- and
intermolecular electron transfer can be easily induced by
valence instability or bistability through external stimuli, such
as changes in temperature, pressure, or light irradiation.33,34
Most importantly, valence instability or bistability-induced
electron hopping can yield ferroelectric polarization (i.e.,
electron ferroelectricity) and further realize ME coupling.
However, to date, there have been no multiferroic/ME-related
investigations on molecular-based CO multiferroic materials or
on their thin film samples. It should be added that
investigations on MEs in multiferroic thin films are of great
importance, mainly because of their outstanding advantages in
sensors, and transducers.1−4 In order to meet the needs of
miniaturization and integration of electronic devices, the
creation of magnetoelectric films is a developing trend. To
date, many inorganic multiferroic materials or films have been
reported with pronounced MEs.5−9 Especially, the success of
the BiFeO3 thin film inspired researchers to develop a series of
multiferroic thin films such as HoMnO3, LuFeO3, etc.10−12
However, there are still series of challenges such as the
preparation process, weak ME coupling, and so on.
In addition to inorganic multiferroic materials, some
molecular-based multiferroic materials, such as metal−organic
frameworks (MOFs), TMCl2-hybrid coordination compounds
(TM = transition metal), and (NH4)2[FeCl5(H2O)], have also
been found with obvious MEs.13−21 Among these reported
multiferroic materials, the so-called charge-ordered (CO)
multiferroic materials (i.e., electronic ferroelectricity) have
also gained the attention of researchers.22−25 In fact, the source
of the electric dipole of CO multiferroics relies on an electronic
correlation rather than covalency. This means that the
ferroelectricity yielded can be manipulated by the orbital
degrees of freedom, charge, and spin of the electron, offering
an attractive possibility for achieving MEs in CO multiferroics.
It is known that the valence oxide LuFe2O4 was the first to
demonstrate CO-related ferroelectricity and pronounced
Received: January 18, 2021
Published: April 13, 2021
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abundant new physical properties and practical applications,
such as device fabrication.
the FeIII (S = 5/2) and FeII (S = 0) sites are coordinated by six
O atoms and six S atoms, respectively (Figure 1c). Therefore,
the nature of electron hopping can be explained by the electron
oscillation between FeIII and FeII sites.37
In this work, we fabricated molecular-based electronic
ferroelectric thin films of [(n-C3H7)4N][FeIIIFeII(dto)3] (1;
dto = C2O2S2) using a simple stamping process. The clear
polarization−electric field (P−E) hysteresis loops were
measured over a wide temperature range from 50 to 300 K
along the in-plane direction of 1. We also achieved room-
temperature ME measurements by switching ferroelectric
domains under a magnetic field in 1 using PFM. This work
will provide new insight into the design of molecular-based
electric ferroelectric/ME thin films.
On consideration of the 2D structure of 1, thin films of 1
were prepared for the characterization of ferroelectric proper-
ties. In detail, thin-film samples of 1 were obtained by
transferring the thin films formed at the air/liquid interface of
the reaction solution to a SiO2/Si wafer substrate by a simple
stamping process.38 The crystalline structure of the thin film
was characterized by X-ray diffraction (XRD), which indicated
that the film of 1 was preferentially oriented along (00l), that
is, the c axis orientation, as shown in Figure 2a, and that the 2D
honeycomb layers stacked alternately along the c axis, as shown
in the schematic of the thin film in Figure 2b.
RESULTS AND DISCUSSION
■
Structure and Electron Hopping. The mixed-valence
compound (n-C3H7)4N[FeIIIFeII(dto)3] (1) was a previously
synthesized compound, which crystallized in the P63 space
group.35 The magnetic FeII and FeIII ions are alternately
interlaced with dithiooxalato groups, forming a two-dimen-
sional (2D) honeycomb [FeIIIFeII(dto)3]− layer (Figure 1a),
Figure 2. (a) XRD scan of the film of 1 grown on a SiO2/Si substrate.
(b) Schematic of the film of 1 on a SiO2/Si substrate. (c) AFM image
of the top surface of 1. (d) SEM cross-sectional microstructure of the
film of 1 grown on a SiO2/Si substrate.
Figure 1. (a) Two-dimensional honeycomb network of 1. (b)
Projection view onto the a−c plane of 1. (c) Diagram of the electron
hopping in 1. Color code: C, gray; O, red; S, yellow; N, blue; FeII,
green; FeIII, orange.
The morphology of the film of 1 was identified by atomic
force microscopy (AFM). As can be seen from Figure 2c, seeds
with sizes of approximately 20 nm homogeneously covered the
substrate and formed a continuous layer. The uniform
distribution of seeds can promote uniform growth of the
whole surface of the supporting body and form a continuous
film. A cross section of film 1 was also obtained using scanning
electron microscopy (SEM), and the SEM image showed that
the thickness of the film of 1 was approximately 200 nm
(Figure 2d). A multilayer structure comprising a Si layer, a
SiO2 layer, and the film of 1 is well distinguished, with clear
interfaces between the layers. As in the case of the outside of
the plane, a similar structure can also be observed on the cross
section.
The UV−vis−NIR absorption spectra for the film of 1 were
measured at 298 K, and a broad absorption band was observed
at 565 nm (Figure S3), which can be ascribed to electron
hopping between FeIII and FeII sites, as seen in {Fe9[W-
(CN)8]6(MeOH)24}·xMeOH and {[FeTp(CN)3]2Co-
(Meim)4}·6H2O.39,40 The electron hopping in the thin film
of 1 was also investigated by measuring the temperature-
dependent capacitance along the in-plane and out-of-plane
and the cations of (n-C3H7)4N+ are intercalated by two nearby
[FeIIIFeII(dto)3]− layers (Figure 1b). The temperature depend-
̈
ence of the Mossbauer spectra revealed that the electron
hopping between FeII and FeIII sites occurred reversibly at
approximately 120 K.36 Temperature-dependent magnetic
susceptibility measurements were performed on a powder
sample of 1 under an applied magnetic field of 0.5 T (Figure
−1
S2). A linear fitting of χm vs T ranging from 150 to 300 K
−1
following the Curie−Weiss law, χm = C/(T − Θ), showed a
Curie temperature of Θ = 16.82 K and a Weiss constant of C =
4.32 cm3 K mol−1 (Figure S2b), revealing the overall
ferromagnetic interaction in 1. With decreasing temperature,
χmT remained nearly constant until ca. 120 K, when a thermal
hysteresis occurred. This observation was in line with a
transition from FeIIIls (S = 1/2) and FeIIhs (S = 2) to FeIIIhs (S =
5/2) and FeII (S = 0) arising from electron hopping between
ls
FeII and FeIII sites.
At temperatures above 120 K, the FeIII (S = 1/2) and FeII (S
= 2) sites are coordinated by six S atoms and six O atoms,
respectively. However, when the temperature is below 120 K,
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directions. As shown in Figure S4, a clear difference between
the in-plane and out-of-plane directions was observable,
showing an obvious capacitance anisotropic behavior in the
film of 1. For the in-plane direction, there was a huge hump of
capacitance over a wide temperature range from 50 to 125 K,
and there was also a corresponding humped peak on the
temperature dependence of dielectric loss curves. However,
only one nearly flat capacitance curve was observed in the out-
of-plane direction. On consideration that electron hopping
between FeII and FeIII sites occurs at ca. 120 K, the capacitance
anomaly along the in-plane direction is thought to be due to
the intralayer electron oscillation between FeII and FeIII sites.
The results also indicate that the temperature could possibly
extend to 50 K for the electron oscillation between FeII and
FeIII sites.
Ferroelectric Properties. The P−E loops for film 1 were
subsequently measured using the positive-up−negative-down
(PUND) method along the in-plane and out-of-plane
directions. The PUND method was used to eliminate the
contributions induced by the small electrical conductivity. To
measure the in-plane P−E loop, the interdigital electrodes were
deposited on the surface of film 1. As shown in Figure 3a, a
six-membered [FeIIIFeII(dto)3]− lattice, the center of the net
negative charge at the center of the six-membered lattice.
Then, an electric dipole oriented from the six-membered lattice
to the [(n-C3H7)4N]+ is formed. Therefore, compound 1 has
an intrinsic spontaneous polarization along the c axis. However,
the center of the net negative charge will change according to
the electron oscillation between FeIII and FeII sites in the six-
membered lattice, resulting in a change in the electric dipole
and polarization. For the polarization reversal, it is understood
that the polarization change was achieved by electron hopping
under an electric field: that is, by the controlled movement of
electrons under an electric field between two adjacent FeII and
FeIII atoms.
To better understand this polarization reversal, electron
hopping is simplified to the electron movement between two
adjacent FeII and FeIII atoms, and the polarization change was
simply induced by electron hopping. The net negative charge
in the intralayer was imposed on the mobile electrons on the
FeIII/FeII sites. Therefore, the polarization change was
indicated as mobile electrons to the static [(n-C3H7)4N]+
positive charge center. As shown in Figure 3b, the total
polarization has two components, one along the in-plane
direction and the other in the out-of-plane direction. In the in-
plane direction, the polarization could be reversed, accom-
panied by an electron position change between FeIII and FeII
sites. Therefore, ferroelectricity is exhibited in the in-plane
direction of the film of 1. The in-plane ferroelectric
polarization was calculated using the point electric charge
model,30 and the estimated polarization is ∼11.7 μC/cm2,
which is close to the experimental value (10.0 μC/cm2) at 50
K (Supporting Information). In the out-of-plane direction,
accompanied by electron movement, the polarization is
constant and is in the same direction, meaning that the
polarization cannot be reversed with electron movement.
Therefore, the ferroelectricity was attributed to electron
hopping between the FeII and FeIII sites in the intralayer
structure.
Figure 3. (a) Hysteresis loops of electric polarization of the film of 1
measured at 300 K in the in-plane direction. (b) Schematic
representation of the dependence of the polarization on the applied
electric field for ferroelectricity of 1.
To further confirm that ferroelectricity was caused by
electron hopping, as a contrasting test, the FeII ions were
replaced by nonmagnetic ZnII ions, leading to the compound
[(n-C3H7)4N][FeIIIZnII(dto)3] (2). Herein, electron hopping
was prohibited between FeIII and ZnII.41 Similarly, the same
method as for 1 was used to prepare a film of 2. The films of 2
grow preferentially along the c axis direction on the substrates
(Figure S7a). Abnormal values were not observed in the
capacitance curves in 2 (Figure S7b), which were both in-
plane. No ferroelectric signals were observed in the in-plane
direction for 2 (Figure S7c,d). The contribution of [(n-
C3H7)4N]+ to polarization can also be excluded. This indicates
that the ferroelectric polarization in 1 can be attributed to the
electron oscillation between the FeII and FeIII sites in the
intralayer structure.
Magnetoelectric Coupling. PFM measurements were
performed on the surface of the film to further reveal the
ferroelectric properties of 1. Out-of-plane and in-plane
responses were measured, which are directly related to the
magnitude and direction of the polarization by the amplitude
and phase signals (Figure 4). The out-of-plane and in-plane
PFM amplitude and phase, as shown in Figure 4a,c,
respectively, proved the static domain structure under zero
field for the film of 1. Obviously, classical domain structures, in
which domain walls have low local amplitudes and the
neighboring domains differ in phase by 180°, were present in
good P−E loop was obtained at 300 K with the electric field
applied along the in-plane direction, which confirmed the
existence of ferroelectric polarization in the in-plane direction.
To verify the reliability of the ferroelectric measurements,
contrasting ferroelectric tests were carried out on the Si/SiO2
substrate and no ferroelectric signal was detected (Figure S6a).
Therefore, 1 was confirmed to be a ferroelectric material. At
the same time, ideal P−E hysteresis loops over a wide
temperature range from 50 to 300 K were also observed
(Figure 3a and Figure S5). By a comparison of the value of the
polarization, it was found that the value decreased gradually
with increasing temperature, which may be caused by
increasing leakage current.
To clarify the source of ferroelectric polarization, the out-of-
plane P−E hysteresis loops were measured on the basis of the
film of 1 fabricated on fluorine-doped tin oxide (FTO)
substrates with a top-down Ga−In alloy electrode. The out-of-
plane P−E data showed normal linear dielectric behavior
(Figure S6b). On consideration that only in-plane P−E
hysteresis loops could be obtained, together with the presence
of electron hopping only along the in-plane direction, it is
reasonable to argue that the origin of ferroelectric polarization
can be ascribed to electron hopping. Accordingly, a possible
polarization model related to the electron hopping between the
FeII and FeIII sites in 1 has been proposed (Figure 3b). Equal
numbers of alternating FeII and FeIII connections coexist in the
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phase amplitude and phase images with H = 0, the domains
apparently changed.
The brown domain area in the phase image shown in Figure
4a mostly reduces and changes to yellow domains in the
corresponding region in Figure 4b; the yellow domains inside
the ellipse in Figure 4c also reduce and change to brown
domains in the corresponding region in Figure 4d. The
corresponding changes can also be observed in the amplitude
image. These color shifts all disclose the shift of the domain
walls, and the polarization evidently changed in some parts of
the region under a magnetic field. However, despite the
modification of ferroelectric domains occurring only in some
regions, the results reveal the pronounced MEs in 1, which
were also systematically observed in other reported materials
studied with PFM, such as (R,R)-[Zn(OAc)(L)Yb(NO3)2]
and CoFe2O4−Pb(Zr0.52Ti0.48)O3.42,43
Meanwhile, partial domain structures clearly revert to their
zero magnetic field states after the magnetic field is removed.
As shown in the ellipse areas of Figure S11, one can see that
the related brown domain areas in the in-plane phase image
under a magnetic field change into yellow domain area after
the field is removed. In addition, the structure of the whole
domain is very similar in shape to the initial state under zero
field. In contrast, the obvious change in domain structures in
the out-of-plane phase image is also observable; however, the
related domain states change into a single domain state, but
not the initial state under zero field (Figure S12). In any event,
these results can further confirm the existence of ME in 1.43,44
The same experiment was carried out for 2. Only in the out-
of-plane direction did the PFM phase images show
approximately 180° domains (Figure S13), indicating polar-
ization perpendicular to the plane, which originated from an
electric dipole oriented from the six-membered
[FeIIIZnII(dto)3]− lattice to the [(n-C3H7)4N]+. There were
no domains along the in-plane direction (Figure S14). These
phenomena all disclose the absence of polarization in the in-
plane direction, which is consistent with the absence of
electron hopping between the FeIII and ZnII sites. Furthermore,
the out-of-plane domains could not be changed by the external
magnetic field (Figure S13). This confirmed that ME coupling
existed in 1. In 1, the strong electronic correlation promoted
ME coupling, and weak spin−orbit coupling was probably the
driving force for ME coupling.
Figure 4. PFM amplitude and phase images of film 1 in the out-of-
plane direction at H = 0 Oe (a) and H = 800 Oe (b) and in the in-
plane direction at H = 0 Oe (c) and H = 800 Oe (d).
the out-of-plane direction of 1. In addition, domain structures
also exist in the in-plane direction of 1. Here, the yellow and
brown regions in the phase image represent regions with
opposite polarization or different directions in their vertical
and lateral components. The static domain structure
distribution is irregular in both the out-of-plane and in-plane
directions. However, the static domain structures are different
in shape, with out-of-plane domains shaped like discrete
islands and in-plane domains shaped like ribbons. The obvious
ferroelectric domains lack a significant correlation with the
topographical images of the film of 1 (Figures S8 and S9). This
result is consistent with the conclusion that polarization has
both in-plane and out-of-plane components (Figure 3b).
The electron hopping between FeIII and FeII sites produces
not only a reversible electrical polarization but also a spin
change, indicating the possibility of ME coupling in 1. Hence,
PFM measurements were carried out under a magnetic field
(H) of 800 Oe (Figure 4b,d) on the film of 1, with the
direction of the magnetic field being parallel to the surface of
film 1. As shown in the topographical diagram in Figure S10,
the perfectly consistent topography reveals that the measure-
ments were carried out in the same zone before and after
application of the magnetic field. In comparison with the PFM
CONCLUSION
■
In summary, a film of [(n-C3H7)4N][FeIIIFeII(dto)3] (1; dto =
C2O2S2) was fabricated. Its in-plane ferroelectric polarization
over a wide temperature range from 50 to 300 K was induced
by electron hopping between the FeII and FeIII sites. When FeII
was replaced with ZnII, the obtained compound [(n-
C3H7)4N][FeIIIZnII(dto)3] (2; dto = C2O2S2) showed no
ferroelectric properties, which further confirmed the ferroelec-
tricity source of 1. Room-temperature ME coupling was
evidenced by controlling ferroelectric domains under a
magnetic field in 1. The present work not only provides a
new insight into the design of molecular-based electric
ferroelectric and magnetoelectric coupling materials but also
takes a solid step toward their practical application in a new
generation of devices.
EXPERIMENTAL SECTION
■
Synthesis of (n-C3H7)4N[FeIIIFeII(dto)3] (1) and (n-C3H7)4N-
[FeIIIZnII(dto)3] (2). KBa[FeIII(dto)3]·3H2O (0.077 mmol) was
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dissolved in 20.0 mL of H2O. The solution was filtered, and a mixed
solution of FeCl2·4H2O (0.16 mmol), (n-C3H7)4NBr (0.26 mmol),
and 10.0 mL of H2O was added. The method of preparing 2 was the
same as that of 1, except for using the appropriate amount of ZnCl2 in
place of FeCl2·4H2O.
Film Fabrication. Si substrates with 300 nm SiO2 and FTO
substrates were cleaned ultrasonically in trichloromethane, deionized
water, acetone, and ethanol for 30 min, respectively, and then dried
under a flow of nitrogen.
The membranes that formed could be observed by the naked eye at
the air/liquid interface. The back sides of the substrates were secured
tightly by a rubber teat and then horizontally positioned in place close
to the self-assembled (n-C3H7)4N[FeIIIMII(dto)3] (M = Fe, Zn)
membrane in a crystallizing dish. The films were then transferred onto
Si substrates with 300 nm SiO2. When the FTO glass was clamped
with tweezers and placed into the mixed solution described above, the
substrate was in horizontal contact with the membrane. The film of 1
was then completely transferred to the FTO substrate.
Xiaofeng Huang − Collaborative Innovation Center of
Chemistry for Energy Materials, State Key Laboratory of
Physical Chemistry of Solid Surfaces, and Department of
Chemistry, College of Chemistry and Chemical Engineering,
Xiamen University, Xiamen 361005, People’s Republic of
China
Yanping Ren − Collaborative Innovation Center of Chemistry
for Energy Materials, State Key Laboratory of Physical
Chemistry of Solid Surfaces, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, People’s Republic of China
Lansun Zheng − Collaborative Innovation Center of
Chemistry for Energy Materials, State Key Laboratory of
Physical Chemistry of Solid Surfaces, and Department of
Chemistry, College of Chemistry and Chemical Engineering,
Xiamen University, Xiamen 361005, People’s Republic of
China
ASSOCIATED CONTENT
Complete contact information is available at:
https://pubs.acs.org/10.1021/jacs.1c00601
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/jacs.1c00601.
Author Contributions
§X.L. and B.W. contributed equally to this work.
Sample preparation, physical measurement methods,
polarization calculations, magnetic tests, UV−vis−NIR
spectral analysis, capacitance responses, measured P−E
hysteresis loops, powdered X-ray diffraction, in-plane
(lateral) PFM amplitude and phase images, out-of-plane
(vertical) PFM amplitude and phase images, and PFM
test of Pb(Zr,Ti)O3 (PZT) (PDF)
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by the National Natural Science
Foundation of China (grant nos. 92061107, 21431005, and
21571150) and the Fundamental Research Funds for the
Central Universities of China (grant no. 20720180030).
AUTHOR INFORMATION
■
REFERENCES
■
Corresponding Authors
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Xinwei Dong − Department of Physics and Institute of
Theoretical Physics and Astrophysics, Xiamen University,
Xiamen 361005, People’s Republic of China;
Email: dongxw@xmu.edu.cn
Haixia Zhao − Collaborative Innovation Center of Chemistry
for Energy Materials, State Key Laboratory of Physical
Chemistry of Solid Surfaces, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, People’s Republic of China;
orcid.org/0000-0002-1688-7713; Email: hxzhao@
xmu.edu.cn
Lasheng Long − Collaborative Innovation Center of
Chemistry for Energy Materials, State Key Laboratory of
Physical Chemistry of Solid Surfaces, and Department of
Chemistry, College of Chemistry and Chemical Engineering,
Xiamen University, Xiamen 361005, People’s Republic of
China; orcid.org/0000-0002-0398-4709;
Email: lslong@xmu.edu.cn
Authors
Xiaolin Liu − Collaborative Innovation Center of Chemistry
for Energy Materials, State Key Laboratory of Physical
Chemistry of Solid Surfaces, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, People’s Republic of China
Bin Wang − Collaborative Innovation Center of Chemistry for
Energy Materials, State Key Laboratory of Physical
Chemistry of Solid Surfaces, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen
University, Xiamen 361005, People’s Republic of China
5783
https://doi.org/10.1021/jacs.1c00601
J. Am. Chem. Soc. 2021, 143, 5779−5785

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
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Journal of the American Chemical Society
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