4 research outputs found
High Performance and Long-Term Stability in Ambiently Fabricated Segmented Solid-State Polymer Electrochromic Displays
This work reports on the performance
of a segmented polymer electrochromic display that was fabricated
with solution-based processes in ambient atmosphere. An encapsulation
process and the combination of structured wells for the polymer electrochrome
and electrolyte layers as well as the use of a preoxidized counter
polymer yields high contrasts and fast switching speeds. Asymmetric
driving–with respect to time–of the display is investigated
for the first time and the degradation effects in the electrochrome
layer are analyzed and addressed to yield a stable device exceeding
100 000 switching cycles. A printed circuit board was integrated
with the display, allowing the device to be run as a clock, where
the segments only required short pulses to switch without the need
for a constant current to maintain its state. Such an application
pairs well with the advantages of electrochromic polymers, drawing
on its high contrast, stability, and ability to maintain its colored
or colorless state without the need for a constant power supply, to
demonstrate the promise as well as the challenges of developing more
sophisticated electrochromic devices
High Performance and Long-Term Stability in Ambiently Fabricated Segmented Solid-State Polymer Electrochromic Displays
This work reports on the performance
of a segmented polymer electrochromic display that was fabricated
with solution-based processes in ambient atmosphere. An encapsulation
process and the combination of structured wells for the polymer electrochrome
and electrolyte layers as well as the use of a preoxidized counter
polymer yields high contrasts and fast switching speeds. Asymmetric
driving–with respect to time–of the display is investigated
for the first time and the degradation effects in the electrochrome
layer are analyzed and addressed to yield a stable device exceeding
100 000 switching cycles. A printed circuit board was integrated
with the display, allowing the device to be run as a clock, where
the segments only required short pulses to switch without the need
for a constant current to maintain its state. Such an application
pairs well with the advantages of electrochromic polymers, drawing
on its high contrast, stability, and ability to maintain its colored
or colorless state without the need for a constant power supply, to
demonstrate the promise as well as the challenges of developing more
sophisticated electrochromic devices
Optimization of PEDOT Films in Ionic Liquid Supercapacitors: Demonstration As a Power Source for Polymer Electrochromic Devices
We
report on the optimization of the capacitive behavior of polyÂ(3,4-ethylenedioxythiophene)
(PEDOT) films as polymeric electrodes in flexible, Type I electrochemical
supercapacitors (ESCs) utilizing ionic liquid (IL) and organic gel
electrolytes. The device performance was assessed based on figures
of merit that are critical to evaluating the practical utility of
electroactive polymer ESCs. PEDOT/IL devices were found to be highly
stable over hundreds of thousands of cycles and could be reversibly
charged/discharged at scan rates between 500 mV/s and 2 V/s depending
on the polymer loading. Furthermore, these devices exhibit leakage
currents and self-discharge rates that are comparable to state of
the art electrochemical double-layer ESCs. Using an IL as device electrolyte
allowed an extension of the voltage window of Type I ESCs by 60%,
resulting in a 2.5-fold increase in the energy density obtained. The
efficacies of tjese PEDOT ESCs were assessed by using them as a power
source for a high-contrast and fast-switching electrochromic device,
demonstrating their applicability in small organic electronic-based
devices
Tuning Color, Contrast, and Redox Stability in High Gap Cathodically Coloring Electrochromic Polymers
The
design of high bandgap electrochromic polymers (ECPs) that
switch from a high energy absorbing colored state to a near-IR absorbing
colorless state requires a challenging balance to be struck between
achieving large changes in the absorption profile while maintaining
sufficiently low oxidation potentials for use in full-color electrochromic
devices. Previous studies on high bandgap ECPs have investigated structure–property
relationships in dioxythiophenes copolymerized with various arylenes.
Here, we expand this understanding by looking more closely at the
effect of the dioxythiophene moiety as well as by varying the substituents
on the arylene moiety. Three ECPs have been synthesized to perform
this study with repeat units composed of electron-rich dimethoxyphenylene
in alternation with dimers of 3,4-dialkoxy- and 3,4-propyleneÂdioxythiophenes,
yielding high gap polymers that are vibrant yellow or orange in the
charge neutral state. Comparing these newly synthesized polymers to
a structurally similar set previously reported, we elucidate the subtle
steric and electronic effects that govern bandgap and redox properties
in dioxythiophene copolymers