2 research outputs found
AC Measurements Using Organic Electrochemical Transistors for Accurate Sensing
Organic
electrochemical transistors (OECTs) have been successfully employed
for a variety of applications , especially chemical and biological
sensing. Although the device response to analytes can be directly
monitored by measuring steady-state channel currents of the devices,
it is challenging to obtain stable signals with high signal-to-noise
ratios. In this work, we developed a novel method for electrochemical
sensing by measuring both the transconductance and the phase of the
AC channel current for the first time. Then we successfully realized
highly sensitive ion strength sensors and dopamine sensors based on
the AC method. Our results indicate that the AC method is more sensitive
than typical DC methods and can provide more stable data in sensing
applications. Considering that the sensors can be conveniently integrated
with AC circuits, this technology is expected to find broad applications
in the future
Synthesis of High-Crystallinity DPP Polymers with Balanced Electron and Hole Mobility
We review the Stille coupling synthesis
of PÂ(DPP2OD-T) (PolyÂ[[2,5-diÂ(2-octyldodecyl)ÂpyrroloÂ[3,4-<i>c</i>]Âpyrrole-1,4Â(2<i>H</i>,5<i>H</i>)-dione-3,6-diyl]-<i>alt</i>-[2,2′:5′,2″-terthiophene-5,5″-diyl]])
and show that high-quality, high molecular weight polymer chains are
already obtained after as little as 15 min of reaction time. The results
of UV–vis spectroscopy, grazing incidence wide-angle X-ray
scattering (GIWAXS), and atomic force microscopy show that longer
reaction times are unnecessary and do not produce any improvement
in film quality. We achieve the best charge transport properties with
polymer batches obtained from short reaction times and demonstrate
that the catalyst washing step is responsible for the introduction
of charge-trapping sites for both holes and electrons. These trap
sites decrease the charge injection efficiency, strongly reducing
the measured currents. The careful tuning of the synthesis allows
us to reduce the reaction time by more than 100 times, achieving a
more environmentally friendly, less costly process that leads to high
and balanced hole and electron transport, the latter being the best
reported for an isotropic, spin-coated DPP polymer