Characterization and simulation of electrolyte-gated organic field-effect transistors

Abstract

In this work we fabricate and characterize field-effect transistors based on the solution-processable semiconducting polymer poly(3-hexylthiophene) (P3HT). Applying two independent gate potentials to the electrolyte-gated organic field-effect transistor (EGOFET), by using a conventional SiO(2) layer as the back-gate dielectric and the electrolyte-gate as the top-gate, allows the measurement of the electrical double layer (EDL) capacitance at the semiconductor-electrolyte interface. We record the transfer curves of the transistor in salt solutions of different concentration by sweeping the bottom gate potential for various constant electrolyte-gate potentials. A change of the electrolyte-gate potential towards more negative voltages shifts the threshold voltage of the bottom-gate channel towards more positive back-gate potentials, which is directly proportional to the capacitive coupling factor. By operating the EGOFET in the dual-gate mode, we can prove the dependency of the EDL capacitance on the molarity of the electrolyte according to the Debye-Hückel theory, and additionally show the difference between a polarizable and non-polarizable electrolyte-gate electrode. With the experimentally obtained values for the EDL capacitance at the semiconductor-electrolyte interface we can model the electrolyte-gate transfer characteristics of the P3HT OTFT.

Ambipolar device simulation based on the drift-diffusion model in ion-gated transition metal dichalcogenide transistors

“…In single crystalline TMDs, such mid-gap states are absent. On the other hand, previous simulations on ion-gated organic transistors used a fixed capacitance induced by the ionic liquids 44,45 , which cannot include the variation of the capacitance due to the modification of the ion distribution by the source-drain bias voltage and the back action from the carriers in semiconductors. The general perspective of the ambipolar transport in MOSFETs has been discussed in ref.…”

Label-free detection of interleukin-6 using electrolyte gated organic field effect transistors

“…38 Please note that the transconductance depends on fixed values, as the channel geometry and VDS, and on the μCG product, which instead can be affected by binding events at the gate electrode.…”

High performing solution-coated electrolyte-gated organic field-effect transistors for aqueous media operation

“…In particular, the two electrical double layers (EDLs) established at both gate electrode/water and water/OSC interfaces are responsible for the electrical tuning of EGOFETs14. Since the aqueous media acts as the effective gate dielectric, a drastic lowering of the operational voltages is intrinsically guaranteed, because the usual EDL capacitance spans from few up to hundreds of μF/cm 2 compared to nF/cm 2 of standard dielectrics5. One direct consequence was the extensive exploitation of surface treatments on both gate electrode and OSC, which directly affects the overall performance.…”