OECTs transistors

The relative lateral dimensions of the different parts of the OECT transistor couple strongly to a number of the crucial performance parameters of the... 

Figure 2. (a) Schematic cross section of an organic field-effect transistor (OFET). (b) Schematic cross section of an organic electrochemical transistor (OECT). The applied source-drain voltage Vd and gate voltage Vg are also shown. 

Fig. 9.1. (Left) the architecture of the PEDOT PSS-based OECT is illustrated viewed from the top and at a cross section, respectively. The area of the PEDOT PSS film, in between the source and drain contact, that is capped by the electrolyte, defines the transistor channel. (Right) the current vs. voltage characteristics of the PEDOT PSS-based OECT. At zero gate voltage, the transistor is in the ON state and at Vg = 0.8 V the channel current is suppressed by more than two orders of magnitude as compared to the ON state current...

In this work, an ionophore-based solvent polymeric membrane is cast on top of the PEDOT PSS channel in order to obtain an ion-selective organic electrochemical transistor (IS-OECT). The polymeric membrane is composed of 2-nitrophenyl octyl ether (o-NPOE, 57.2% ww), poly(vinyl chloride) (PVC, 27.9% ww), V.. V.. V. . V -i( I i i( ycloli( xyl-3-oxapentanedianii(le (ETH 129, 9.6% ww) and potassium tetrakis(4-chlorophenyl)borate (KTpCIPB, 5.4% ww), where ETH 129 is a Ca2+-selective ionophore. The channel region of the transistor that is coated by the Ca2+-selective membrane is immersed in an aqueous solution containing 0.1 M KC1 as a background electrolyte and... 

The organic-based OECT, reported here, can handle remarkably higher power than its OFET relatives. As an example, an Orgacon (particular grade of PEDOT PSS from AGFA)-based transistor with active channel size 0.5 x 0.5 mm2 can handle a switching power of up to 20 mW. Above this power level breakdown occurs, most likely due to thermal stress. The transistor can also handle voltages of up to 70 V as well as currents up to 1 mA. 

Figure 31 A voltage applied at the gate electrode (l/g) of an OECT causes K ions to go through the gramicidin channels and change the drain current (1 ). No response is observed for Ca, as gramicidin is not permeable to divalent ions. When a 1V pulse at the gate destroys the membrane, it can be seen that the transistor itself cannot discriminate mono- from divalent ions.

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