Assessment of the Testing Methods for Evaluating the Performance of Organic Electrochemical Transistors

Abstract

As a next-generation electronic device, the organic electrochemical transistor (OECT) is widely spreading in laboratory research and has many practical applications because of the advantages of its simple structure, low operating voltage, and high biocompatibility. However, the evaluation of the performance of OECTs is generally chaotic since there are many testing methods that may yield different results. Herein, we reveal that the testing protocols may largely affect the obtained results of the same OECT. An increase in the sweeping speed of the gate voltage could lead to a drop in the measured performance of OECTs. When a pulsed voltage was applied on the drain electrode, a degradation in the performance of OECTs could also be observed at a short pulse width. This work clarifies the influence of testing methods on the performance evaluation of OECTs. As a result, the development of the field of the synthesis of OECTs may be significantly promoted.

Improved Organic Electrochemical Transistors via Directed Crystallizable Small Molecule Templating

“…Figure A plots the maximum transconductance ( g m , max) from the OECT devices of different dimensions against the geometry factors from eq . Fitting the slope of the linear fit to this data yields the materials' figure of merit, mobility volumetric capacitance product (μ C *), and is the most common characterization technique for OECTs in the literature, , despite recent concerns that it overestimates mobility . Representative transfer and output curves of each formulation are shown in Figures S12 and S13, respectively.…”

“…Fitting the slope of the linear fit to this data yields the materials' figure of merit, mobility volumetric capacitance product (μC*), and is the most common characterization technique for OECTs in the literature, 35,54 despite recent concerns that it overestimates mobility. 55 Representative transfer and output curves of each formulation are shown in Figures S12 and S13, respectively. For accurate μC* determination, determination of thickness is essential.…”

Hydrogel-Gated FETs in Neuromorphic Computing to Mimic Biological Signal: A Review

“…To emulate ion-dynamics-based biological synapses that are flexible, inexpensive, and lightweight, an organic synaptic transistor stands out as the most suitable device choice that has recently been a growing development in the use of 3T transistors in synaptic simulation techniques [ 22 , 23 , 24 , 52 , 53 ]. Additionally, transistors offer precise device selection through low operating voltage, effectively addressing adjacent cell crosstalk in two-terminal synaptic electronic devices [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

“…Over the last few decades, SiO 2 -based gate dielectric field effect transistors have been widely used, although they exhibit a comparatively low capacitance due to the limited level of carrier accumulation charges experienced by applying gate voltage [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 71 , 72 , 73 ]. Being that they are soft and tunable and have high dielectric capacitance due to the production of EDL in the dielectric and channel region, organic field effect transistors (OFET) represent the materials that facilitate the coupling and transportation of both electronic and ionic charges [ 24 ].…”

“…For implementation at the hardware level, various types of neuromorphic devices, such as two-terminal devices [ 6 ] and 3T devices, have been proposed as potential foundational components for synaptic bionics and applications in neuromorphic engineering, including phase change memory (PCM), resistive random access memory (RRAM) [ 13 , 14 , 15 , 16 , 17 ], magnetoresistive access memory (MRAM) [ 18 ], and so on, while 3T devices include floating-gate transistor devices [ 19 , 20 ], ferroelectric field effect transistors (FeFETs) [ 21 ], electrolyte-gated transistors (EGTs) [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ], and hydrogel-gated field effect transistors (HGFETs) [ 29 , 30 , 31 , 32 ]. Due to the physical separation of the pre- and postsynaptic terminal, the 3T device is the best choice to simulate various neural activities, such as short-term plasticity (STP) and long-term plasticity (LTP), excitatory postsynaptic current (EPSC), and spike-timing dependent plasticity (STDP) [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Hydrogel-gated field-effect transistors (HGFETs), among the diverse array of 3T devices, have been explored for widespread practical application in bioelectronics owing to their resemblance to biological synapses [ 12 , 29 ].…”