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\begin{document}

\title{Multifunctional Polyimides for Resistive Switching Memory Devices Based
on Flexible Transparent Polyimide--AgNWs Hybrid Electrodes}



\author[1]{Guoshu Liu}%
\author[1]{Jinghong Zhang}%
\author[2]{Zuxin She}%
\author[3]{Liangyi Peng}%
\author[1]{Lunjun Qu}%
\author[1]{Kaiti Wang}%
\author[1]{Hailong Tang}%
\author[1]{Chaolong Yang}%
\affil[1]{Chongqing University of Technology}%
\affil[2]{Southwest Technology and Engineering Research Institute}%
\affil[3]{Sinopec Lubricant Co Chongqing Branch}%


\vspace{-1em}



  
  \date{May 16, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
With the quick development of flexible memory electronics,
multifunctional organic materials have been the necessary for
fabricating electronics. In this work, the highly transparent and
flexible electrode was successfully prepared by coating the
high-performance silver nanowires (AgNWs) onto the colorless polyimide
(PI) substrate. The prepared flexible PI-AgNWs electrodes exhibited a
low sheet resistance of 15 \selectlanguage{greek}Ω/\selectlanguage{english}sq with the high transparency of 68 \% at
the wavelength of 400 nm. A novel kind of polyimide TPC6FPI was
successfully synthesized and characterized with excellent thermal
stabilities and high glass transition temperature (T\textsubscript{g})
above 250 \selectlanguage{ngerman}°C. Furthermore, a kind of flexible transparent PI-AgNWs/
TPC6FPI/Al resistive memory device was prepared and exhibited excellent
SRAM switching behavior with the threshold voltage of around 2.1V and
the ON/OFF current ratio of \textasciitilde{}10\textsuperscript{-4},
which indicated that multifunctional PI-based memory device showed the
potential to the wearable devices.%
\end{abstract}\selectlanguage{ngerman}%



\sloppy


\textbf{1 Introduction}

Nowadays, flexible electronics are widely used in our daily lives
because of their better convenience and providing us more bright
horizons.\textsuperscript{{[}1-2{]}} With the rapid growth of digital
information over the past decades, the traditional optical and magnetic
storage technologies have almost reached their theoretical and physical
limits, which cannot meet the huge demands of memory devices for
high-density, fast response and flexible data
storage.\textsuperscript{{[}3-5{]}} Compared with the traditional memory
devices, resistive random-access memory (RRAM) devices with a top
electrode/active layer/bottom electrode sandwiched
structure\textsuperscript{{[}6{]}}, play an important role in the
next-generation digital memory devices due to their high performance,
high reliability\textsuperscript{{[}7{]}}, fast
operation\textsuperscript{{[}8{]}}, excellent
scalability\textsuperscript{{[}9{]}} and durable
flexibility\textsuperscript{{[}10{]}}, and attract much attention as one
of the most promising candidates such as the resistor, capacitor and
transistor, etc.\textsuperscript{{[}11-13{]}} However, the performance
of flexible RRAM devices still faces many challenges such as the serious
degradation of reliability during continued deformation.

To meet the increasing requirement of flexible RRAM devices, polymers as
the active layer are more favorable than other materials due to their
low cost, intrinsic flexibility and large area fabricating
capability.\textsuperscript{{[}14-16{]}} Polymer memory materials can
store data through the conversion between the low and high current
states between two electrodes by the applied voltage, which can be
assigned as ``0'' and ``1'' or ``OFF'' state and ``ON''
state.\textsuperscript{{[}17-21{]}} In recent years, functional
polyimides (PIs) are regarded as the most promising polymeric memory
materials due to their excellent thermal
resistance\textsuperscript{{[}22{]}}, chemical
stability\textsuperscript{{[}23{]}}, mechanical
durability\textsuperscript{{[}24{]}} and
flexibility\textsuperscript{{[}25{]}}. More importantly, PIs with the
special donor-acceptor (D-A) type molecular structures exhibiting
stronger intramolecular and intermolecular charge transfer (CT) effects
are more promising for the flexible memory
devices.\textsuperscript{{[}26-29{]}} Up to now, a large number of PIs
exhibit various kinds of memory properties, including the volatile
memory properties (Dynamic Random-Access
Memory\textsuperscript{{[}31{]}} (DRAM), Static Random Access
Memory\textsuperscript{{[}32{]}} (SRAM)) and the non-volatile memory
properties (FLASH\textsuperscript{{[}33{]}}, Write Once Read
Many\textsuperscript{{[}34{]}} (WORM)). However, most reported PI based
memory devices are rigid and non-wearable, which limits their
application in flexible electronics.\textsuperscript{{[}35{]}}

In order to reach the demand of wearable intelligent electronic memory
devices, advances in electrodes are essential to enhance the properties
of both high conductivity, flexibility and transmittance. The
polymer-based electrodes have attracted great attention by investigating
indium tin oxide (ITO)\textsuperscript{{[}36{]}}, carbon nanotubes
(CNTs)\textsuperscript{{[}37{]}}, graphene\textsuperscript{{[}38{]}},
and metallic nanowires\textsuperscript{{[}39{]}}, etc. Especially,
silver nanowires (AgNWs) have been considered as the most potential
candidates in the future.\textsuperscript{{[}40-42{]}} However, the poor
adhesion properties of AgNWs and the lower glass transition temperature
(\emph{T} \textsubscript{g}) of flexible substrates are further
restricted to the development of the polymer-AgNWs electrodes.

Hence, in this work, we designed and synthesized a kind of thermally
stable and colorless polyimide (PI) with a high\emph{T}
\textsubscript{g} and high transmittance in the visible light area,
which was chosen to prepare flexible PI--AgNWs hybrid electrodes. Then,
a novel kind of polyimide memory material (TPC6FPI) was prepared by the
polycondensation of the diamine
4,4'-((4-(diphenylamino)phenyl)methylene)dianiline (TPCDA) and the
dihydride 2,2-bis(3,4-anhydrodicarboxyphenyl)-hexafluoropropane (6FDA),
which was used for the flexible resistive memory device with a
sandwich-like structure fabricated by casting TPC6FPI as active layers
between the bottom PI--AgNWs hybrid electrodes and top Al electrodes.
Furthermore, the performance of PI-based flexible memory devices
exhibiting SRAM type memory behavior were systematically studied and
evaluated. This study aimed to provide an effective and reliable method
for the performance optimization of multifunctional flexible PI based
memory devices.

\textbf{2 EXPERIMENTAL}

\textbf{2.1 Synthesis of colorless PI}

As shown in Figure 1a, the colorless polyimide TFBPI used in this work
was synthesized according to a traditional two-step by thermal
imidization as follows: 1.0410 g (2 mmol) of
4,4'-{[}(isopropylidene)bis(p-phenyleneoxy){]}diphthalic dianhydride
(BPADA) and 0.6404 g (2 mmol) of
2,2'-Bis-trifluoromethyl-biphenyl-4,4'-diamine (TFMB) were added into a
solution of N,N-dimethylformamide (DMF) (20 wt\% solid content) under a
nitrogen (N\textsubscript{2}) flow to react over 12 h to form polyamide
acid (PAA) at room temperature. The resulting PAA solution was coating
on a glass substrate to form TFBPI thin film by raising the temperature
slowly to 300 \selectlanguage{ngerman}°C to complete the thermal imidization.

\textbf{2.2 Preparation of AgNWs}

Silver nanowires were synthesized by the modified polyol process: 2 g of
polyvinylpyrrolidone (PVP) was added into ethylene glycol and glycerol
mixed solution (50 mL) stirred at 130 °C to dissolve under a
N\textsubscript{2} flow. After cooling to the room temperature, 0.1 g of
silver nitrate (AgNO\textsubscript{3}) and (NaBr) 0.5 mL were added unto
the reactor and stirred for 0.5 h. Finally, the mixed solution was moved
into vacuum oven for an oxidation reaction over 6 h at 150 °C. The
resulting AgNWs were obtained and washed by ethanol with centrifugation
filtration 5 times to remove the residual PVP and silver nanoparticles.

\textbf{2.3 Preparation of PI-AgNWs hybrid electrodes}

The AgNWs were firstly transferred from ethanol to DMF by using a
solvent exchange method. And the weight fraction of the AgNWs in DMF
solution with 1.0 mg/mL was modulated through thermogravimetry analysis.
Then, the AgNWs solutions were coated on the TFBPI substrates, and
performed thermal annealing at 200 °C for 0.5 h under inert condition to
decrease the electrical resistance of the PI- AgNWs hybrid electrodes.

\textbf{2.4 Synthesis of TPC6FPI memory materials}

The diamine TPCDA was synthesized according to our reported
work\textsuperscript{{[}16{]}} with high efficiency, and the detail
synthesis process (\textbf{Scheme S1} ), structure characterization
(\textbf{Figure S1} ) and measurement method were detailed described in
Supporting Information. TPC6FPI was prepared by the chemical imidization
as follows: 0.2221 g (0.5 mmol) of 6FDA and 0.2206 g (0.5 mmol) of TPCDA
were added into DMF solution (20 wt\% solid content) to stirred for 12 h
to form PAA solution. Then, acetic anhydride (1 mL) and triethylamine
(0.5 mL) were added and the imidization reaction proceeded over 48 h at
room temperature. The resulting polyimide solution was poured into 250
mL of ethanol giving a light-yellow precipitate, which was collected by
filtration.

\textbf{2.5} \textbf{Fabrication of} \textbf{PI-AgNWs/TPC6FPI/Al memory
device}

The flexible memory device was fabricated on AgNWs-coated colorless PI
with the configuration TFBPI-AgNWs/TPC6FPI/Al. The active layer was
fabricated by spreading a 50 mg/mL TPC6FPI solution in DMF onto the
TFBPI-AgNWs substrate using a spin coater set at 2000 rpm. the
spin-coated films were thermally treated under vacuum at 150 °C for 1 h
to remove the remaining solvent. The thickness of the TPC6FPI film was
about 40 nm. Finally, the sandwich devices were fabricated by vacuum
evaporation of a thin Al layer (ca. 200 nm) through a shadow mask onto
the polymer surface as the top electrode.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

\textbf{Figure 1} (a) The synthetic scheme for the synthesis of
colorless polyimide TFBPI; (b) The scheme of the procedure for the
transparent TFBPI-AgNWs hybrid electrodes; (c) Transmittance at 800 nm
wavelength, sheet resistance of AgNWs suspension with different
concentrations ranging from 0.1 mg/mL to 2.0 mg/mL; (d) UV-vis
transmittance spectra of TFBPI and TFBPI-AgNWs; (e) The XRD pattern of
AgNWs and TFBPI-AgNWs.

\textbf{3 RESULTS AND DISCUSSION}

\textbf{3.1 Properties of the colorless TFBPI}

The colorless TFBPI used as substrate materials in this work were shown
in \textbf{Figure 1a} and characterized by FT-IR in \textbf{Figure S2} .
The FT-IR characteristic peaks around 1780 cm\textsuperscript{-1}, 1715
cm\textsuperscript{-1} and 1370 cm\textsuperscript{-1}, were attributed
to the imide groups. There were no peaks of amino groups at 3500
cm\textsuperscript{-1} appeared, which indicated TFBPI was imidized
completely. The TFBPI exhibited excellent solubility in common organic
solvents, such as DMF, DMSO and NMP, which provided an easy blending
method with AgNWs. The TFBPI showed excellent thermal stabilities, and
the diagrams of the thermogravimetric and thermomechanical analyses were
depicted in \textbf{Figure S3} and \textbf{S4} , respectively. The 5
wt\% decomposition temperatures (T\textsubscript{d5\%}) and \emph{T}
\textsubscript{g}values of TFBPI were 510 \selectlanguage{ngerman}°C and 260 °C, indicating that
the PI exhibited highly thermal stability. The optical properties of
TFBPI were investigated by ultraviolet-visible (UV-Vis) absorption and
transmittance. The optical transmittance of TFBPI thin film at 400 nm is
76 \% and the ultraviolet-visible cutoff wavelength of 80 \% is 432 nm.
And the maximum absorption at 306 nm and the edge absorption 341 nm,
indicating the charge transfer effect depressed to result in a colorless
TFBPI.

\textbf{3.2 Properties of the TFBPI-AgNWs hybrid based transparent
electrode}

The scheme of the procedure and the transparency of the TFBPI-AgNWs
hybrid electrodes was shown in \textbf{Figure 1b} . The AgNWs were
prepared with a modified polyol process by the ethylene glycol and
glycerol used as the reductant and solvent, the NaBr used as the oxygen
scavenger and PVP used as the capping agent. The obtained PI-based
flexible electrodes with different amounts of AgNWs were summarized in
Figure 1c. With the increasing concentrations of AgNWs from 0.1 mg/mL to
2.0 mg/mL, the transmittance of PI-based flexible electrodes was cut
down from 88 \% to 42\% at 800 nm. At the same time, the sheet
resistance of flexible electrodes was decreased quickly from
\textasciitilde{}10\textsuperscript{9} \selectlanguage{greek}Ω/\selectlanguage{english}sq to 15 \selectlanguage{greek}Ω/\selectlanguage{english}sq at the
concentrations of 1.0 mg/mL, which was comparable to the commercial ITO
electrodes to meet the performance on flexible substrates for the
resistive memory applications. As we all knew, it was rare difficult for
flexible PI-AgNWs electrodes to achieve a high transmittance with low
resistance simultaneously due to the dilemma relationship between
transmittance and conductivity. Therefore, in this work, 1.0 mg/mL of
AgNWs in DMF solution was chosen to prepare flexible TFBPI-AgNWs hybrid
based transparent electrode. Compared to the TFBPI thin film, the
transmittance of the TFBPI-AgNWs hybrids at 400 nm was down to 67 \%,
and the maximum transmittance was still beyond 70 \%, as shown
in\textbf{Figure 1d} . The inset image of TFBPI thin film and TFBPI-AgNW
flexible electrode suggested the synthesized polyimide exhibited
excellent transparency. And the XRD patterns of TFBPI-AgNW flexible
electrode was similar with the AgNWs except for the wide dispersion peak
of polyimide around 22\selectlanguage{ngerman}°, which indicated that the cell structure of
AgNWs was not changed by thermal annealing with high temperature.

The morphology of the AgNWs was measured by SEM and TEM, and these
images were depicted in \textbf{Figure 2} . The obtained AgNWs had an
average diameter around 50 nm and an average length of 30 nm, suggesting
that the average aspect ratio of these AgNWs was around 600, which was
high enough for the flexible transparent electrodes. And the selected
area electron diffraction (SAED) image of AgNW indicated that the
prepared electrode showed highly ordered lattice and interface.
Therefore, the TFBPI-AgNW flexible electrode was prepared with high
conductivity and transparency, which exhibited the potential application
for the flexible electronics.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

\textbf{Figure 2} (a), (b) and (c) SEM images of the synthesized AgNWs
with 1.0 mg/mL; (d) and (e) TEM images of the synthesized AgNWs with 1.0
mg/mL; (f) Selected area electron diffraction (SAED) image of AgNWs.

\textbf{3.3 Properties of TPC6FPI memory materials}

The polymer TPC6FPI was synthesized by chemical imidization, as shown
in\textbf{Figure 3a} . TPC6FPI exhibited good solubility in a variety of
polar solvent such as DMF and DMSO, and the intrinsic viscosities of
TPC6FPI was of 0.82 dL/g. The high solubility was attributed to the
introduction of bulky side-chain triphenylamine group in the polymer
structure. The \emph{T} \textsubscript{d5\%} and\emph{T}
\textsubscript{g} values of TPC6FPI were 489 \selectlanguage{ngerman}°C and 252 °C,
respectively, as shown in \textbf{Figure 3b} and \textbf{3c} . The
optical spectra of the TPC6FPI in thin film state and in DMF solution
were shown in \textbf{Figure 3d} , \textbf{3e} and \textbf{3f} . TPC6FPI
exhibited the absorption peak maxima at 266 nm in solution which was the
assignable to the \selectlanguage{greek}π--π\selectlanguage{english}* transition. And the middle absorption peak
around 300 was belong to n--\selectlanguage{greek}π\selectlanguage{english}* intramolecular charge transfer (CT)
effect, which even showed the yellow color due to stronger the
intermolecular CT effect in thin film state. Thus, the optical band gap
of TPC6FPI was estimated to be 3.35 eV with the initial absorption
wavelength at around 370 nm. The emission spectra of TPC6FPI in DMF
solution was obtained with the maximum excitation wavelength of 393 nm.
TPC6FPI exhibited intense emission peaks at 433 nm, consistent with the
fact that the triphenylamine derivatives was efficient fluorescence
chromophores.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

\textbf{Figure 3} (a) Synthesis structure of TPC6FPI; (b) TGA curves and
(c) DSC curves of TPC6FPI at a scan rate of 20 \selectlanguage{ngerman}°C/min under
N\textsubscript{2}; (d) UV-vis. transmittance and (e) absorption spectra
of TPC6FPI in thin film state and in DMF solution
(10\textsuperscript{-5} M); (e) photoluminescence curves of TPC6FPI in
DMF solution (10\textsuperscript{-5} M).

\textbf{3.4 Memory device characteristics ofPI-AgNWs/TPC6FPI/Al}

The memory effects of TPC6FPI were demonstrated by the current--voltage
(I--V) characteristics of a flexible PI-AgNWs/TPC6FPI/Al device. The
PI-based memory device can store data based on the high (``ON'' and low
``OFF'') bistable conductive state responses to the external applied
voltages.\textsuperscript{{[}8,12,23{]}} \textbf{Figure 4a} exhibited
the typical I--V curves of the memory devices fabricated with TPC6FPI.
The I--V characteristics were measured by scanning the voltage from 0 to
±4 V. As shown in \textbf{Figure 4b} , initially, the device was in the
OFF state (``0'' signal in data storage) with a current in the range
from \textasciitilde{}10\textsuperscript{-11} to
\textasciitilde{}10\textsuperscript{-7} A with the voltage swept
increasing from 0 V (sweep 1). When the voltage raised further, a sharp
increase in current at a threshold voltage of about 2.1V, which
indicated that the transition from the OFF state to the ON state (``1''
signal in data storage) occurred current from
\textasciitilde{}10\textsuperscript{-6} to
\textasciitilde{}10\textsuperscript{-5} A. The electronic transition
from the OFF state to the ON state was served as the ``writing''
process. Furthermore, the flexible device maintained the ON state under
the positive voltage scan (sweep 2) from 4 V to 0, almost keeping the
current curves on conductive state. After the applied voltage was turned
off about 1 minutes, the device relaxed to the OFF state again. The
memory device could be reset from the initial OFF state to ON state by
the application of a reverse sweep (sweep 3) at -2.4 V. the following
sweep from -4 V to 0V (sweep 4) was still stable at high conductivity.
Therefore, the flexible PI-based memory device which kept the OFF and ON
state was randomly accessible and volatile, which suggested that the
resistive switching behavior was regarded as the static random-access
memory (SRAM) characteristic.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

\textbf{Figure 4} (a) Schematic diagram of the for the flexible
PI-AgNWs/TPC6FPI/Al memory device; (b) Current--voltage (I--V)
characteristics of the memory device with an electrode are of 0.25
mm\textsuperscript{2}; Retention characteristics of both ON and OFF
states for the memory device under a constant stress (1.0 V) at room
temperature.

The I-V characteristics were also found to have good reproducibility,
except for the slight variations in switching threshold voltages
associated with the sheet resistance of flexible PI-AgNWs electrodes, as
shown in \textbf{Figure S6} and \textbf{S7} . In addition, the flexible
memory device maintained an ON/OFF current ratio as high as
10\textsuperscript{4} at 1 V, and the no obvious degradation in current
density was observed for both the ON and OFF states over a 2 h period
(\textbf{Figure 4c} ).

Furthermore, the charge transport mechanism could be obtained from the
I--V curves in OFF and ON states according to the reported various
conduction models in the literature. As shown in \textbf{Figure 5a} ,
the OFF states for the PI-AgNWs/TPC6FPI/Al device exhibited the space
charge limited current model\textsuperscript{{[}6{]}} (SCLC, from 0 to
2.0 V), which was descript by the equation as follow:\(I=9A\varepsilon\varepsilon_{0}\mu V^{2}/8d^{3}\),
where \emph{d} was thickness of active layer, \selectlanguage{greek}\emph{μ} \selectlanguage{english}was the carrier
mobility of polymer, \selectlanguage{greek}εε\selectlanguage{english}\textsubscript{0} was the absolute dielectric
constant. On the other hand, as shown in \textbf{Figure 5b} , the
current in the ON state was almost linear in dependence on applied
voltage just as the ohmic model\textsuperscript{{[}23{]}}, which
indicated that the ON state the charge transport dominated similarly as
metallic conduction.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}

\textbf{Figure 5} (a) Experimental and fitted data of I--V curves for
the memory devices in the OFF states with the

SCLC model; (b) Experimental and fitted data of I--V curves for the
memory devices in the ON states with the ohmic current model; (c)
Calculated molecular orbitals (isovalue=0.05) and (d) the plausible
electronic transition processes occurred on TPC6FPI (Note: Blue and
green isosurfaces represent hole and electron distributions,
respectively); (e) Electrostatic potential (ESP) surface of TPC6FPI.

The above results suggested that the bipolar ON and OFF switching
behaviors of TPC6FPI film could be simulated well according to proper
theoretical model. Geometry optimization of TPC6FPI was realized by DFT
with dispersion-corrected density functional theory (DFT-D3) at the
B3LYP-D3/def2-SVP level, and their excitation energies were calculated
at the CAM-B3LYP/def2-SVP level with TD-DFT
method.\textsuperscript{{[}43-44{]}} The detail progress of calculation
was descripted in the Supporting Information. As shown in \textbf{Figure
5c} , the highest occupied molecular orbital (HOMO) and HOMO+4 mainly
located on the triphenylamine unit, which was the donor cell of the
structure of TPC6FPI. While the lowest unoccupied molecular orbital
(LUMO) and the LUMO+2 distributed on the phthalimide unit completely,
which was the acceptor cell of the structure of TPC6FPI. It was noted
that the switching behavior between the OFF state and ON state
correspond to electronic transition from the ground state to the excited
state. The electron was easily excited from the HOMO to LUMO+4 by the
applied bias reaches at the threshold voltage. However, the excited
state tended to relax to LUMO by internal conversion leading to the
forming the charge transfer (CT) effect. The charge-transfer (CT)
complex was beneficial to stable the ON state. After the applied voltage
was turned off, the charge-transfer (CT) complex was slowly returned to
the initial state. This progress was descripted in \textbf{Figure 5d} by
the hole-electron analysis to fully characterize electron excitations.
It was noted that blue and green isosurfaces represent hole and electron
distributions, respectively.\textsuperscript{{[}45{]}} As shown
in\textbf{Figure 5e} , The Electrostatic potential (ESP) surfaces showed
that TPC6FPI consisted mainly of the positive ESP region (red
color)\textsuperscript{{[}46{]}}, with special independent negative
regions (blue color) mainly arising from the sp\textsuperscript{2}
hybridized O atoms in the phthalimide unit. These negative ESP regions
suggested that concentrated local electron densities near the
phthalimide group possessed a certain electron-withdrawing ability,
suggesting that electrons would be transferred from the triphenylamine
moiety to the phthalimide moieties under excitation. Therefore, the
separation of hole and electron was easy to form a charge transfer
excited state, which was the characteristic of the structure of
polyimide. In other word, the strong charge transfer effect of
polyimides was the essence of resistive switching memory device.

\textbf{4 Conclusion}

In conclusion, introducing the prepared the AgNWs on to colorless PI
through a facile solution casting method was demonstrated as an
effective way to prepare flexible transparent electrodes in this work.
The resulting flexible PI-AgNWs hybrid electrodes exhibited high
transparency and high electrical conductivity with the sheet resistance
of 15 \selectlanguage{greek}Ω/\selectlanguage{english}sq. In addition, the multifunctional polyimide TPC6FPI was
synthesized and proved as a novel kind of memory materials. The
PI-AgNWs/TPC6FPI/Al resistive memory device was successfully prepared
and exhibited excellent SRAM switch behavior, which indicating that the
flexible transparency PI-AgNWs hybrid electrodes afforded the potential
to resistive switching memory devices and served as the electrodes for
wearable devices.

\textbf{Supporting Information}

The supporting information for this article is available on the WWW
under https://doi.org/10.1002/eng2. xxxxx.

\textbf{Acknowledgement}

The authors are grateful for the financial supports by the National
Natural Science Foundation of China (Grant No. 52003032 and 22275025),
the Science and Technology Research Program of Chongqing Municipal
Education Commission (KJQN202001103, KJQN202101106 and KJQN202001104),
the Natural Science Foundation of Chongqing (cstc2020jcyj-msxmX0312 and
cstc2020jcyj-msxmX0556), Innovation Research Group at Institutions of
Higher Education in Chongqing (CXQT19027) and Scientific Research
Foundation for Chongqing University of Technology (2019ZD106).

\textbf{CONFLICT OF INTEREST}

The authors declare no conflict of interest

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