Organic electrochemical transistors (OECTs)
Organic electrochemical transistors (OECTs) are increasingly studied as transducers in sensing applications. While much emphasis has been placed on analyzing and maximizing the OECT signal, noise has been mostly ignored, although it determines the resolution of the sensor. The major contribution to the noise in sensing devices is the 1/f noise, dominant at low frequency. In this work, we demonstrate that the 1/f noise in OECTs follows a charge-noise model, which reveals that the noise is due to charge fluctuations in proximity or within the bulk of the channel material.
(a) Device schematic and measurement setup for the noise characterization. (b) Conductance G (black squares, left axis) and transconductance gm (red circles, right axis) versus the liquid-gate potential VLG measured for a 25 μm (width) × 25 μm (length) OECT. (c) Power spectral density of the voltage fluctuations SV versus frequency f for the OECT in (b) gated to the conductance values specified in the legend. The black dashed line indicates a 1/f dependence. The majority of the noise spectra exhibit a 1/fα characteristic, with α≈1 and only a few exceptions showing α≈1.5 in the low-frequency range. The scattering peaks are attributable to the intrinsic noise of the power line matching 50 Hz and multiples of it.
Dr Michele Sessolo, Dr Henk Bolink, Insititue of Molecular Science (ICMol), Valencia, Spain
Charge Noise in Organic Electrochemical Transistors
Ralph L. Stoop, Kishan Thodkar, Michele Sessolo, Henk J. Bolink, Christian Schoenenberger, and Michel Calame.
Phys. Rev. Applied, 7, 14009 (2017)