Congratulations to Ralph Stoop and Michele Sessolo. Their paper on “Charge noise in organic electrochemical transistors” will appear in Phys. Rev. Applied.


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 fuctuations in proximity or within the bulk of the channel material. We present the noise scaling behavior with gate voltage, channel dimensions and polymer thickness. Our results suggest the use of large area channels in order to maximize the signal-to-noise-ratio
(SNR) for biochemical and electrostatic sensing applications. Comparison with literature shows that the magnitude of the noise in OECTs is similar to that observed in graphene transistors, and only slightly higher compared to Carbon nanotubes and Silicon nanowire devices. In a model ion-sensing experiment with OECTs, we estimate crucial parameters such as the characteristic SNR and corresponding limit of detection.


Device schematic and measurement setup for the noise characterization. (b) Conductance G (black, left axis) and transconductance gm(red, right axis) versus liquid gate potential V_lg measured for a 25 um x 25 um OECT. (c) Power spectral density of the voltage fluctuations S_V versus frequency f for the OECT in (b) gated to different conductance values as given in the legend. The black dashed line indicates a 1/f dependence. The scattering peaks are due to the intrinsic noise of the power line matching 50 Hz and multiples of it.


Charge Noise in Organic Electrochemical Transistors
Ralph L. Stoop, Kishan Thodkar, Michele Sessolo and Henk Bolink, Christian Schonenberger and Michel Calame
to appear in Phys. Rev. Applied

Just accepted: Charge noise in organic electrochemical transistors