Optimum Design of Organic Electrochemical Type Transistors for Applications in Biochemical Sensing

Abstract

This paper addresses the issue of optimizing various performance parameters involved in the design of organic electrochemical type transistors based on the conducting polymer, poly (3,4-ethylenedioxythiophene): poly(styrene sulfonate)(PEDOT:PSS) for applications in biochemical sensing. We report the effect of device contact geometry, gate to channel length ratio "L g /L," and analyte distance from the source electrode "x," on the device sensitivity and response time.

Organic Electrochemical Transistors for In Vivo Bioelectronics

“…An obvious drawback of the TC geometry is the direct current pathway between the gate and source/ drain electrodes, which can contribute to high leakage currents. However, in some cases, the TC geometry has been exploited for biological sensing [60][61][62] and integrated circuits. [63] On the other hand, the BC geometry is mostly preferred, partly because, in this case, prefabricated test chips (consisting of patterned source/drain electrodes) can be used and the fabrication process then only requires the deposition of the polymer channel layer.…”

Liquid electrolyte positioning along the device channel influences the operation of Organic Electro-Chemical Transistors

“…biasing (in our case, applied electric fields E are less than 425 10 À1 V cm À1 ) the OECT operation is dominated by the ionic 426 circuit and, as expected, the current modulation is always 427 enhanced in the case of the lowest electrodes spacing. 428 Badhwar and Narayan [12] have already observed the 429 worsening of the current modulation for a near-to-drain where I on is I ds at V gs = 0 V and I off is I ds at V gs > 0 V) [10]. In …”

“…73 The ion-to-electron transduction is based on the injection 74 of ionic species from the electrolyte towards the under- 75 neath polymeric film upon the application of a gate bias. 76 The typical OECTs exploit channels made of a highly doped 77 polymer, the p-type oxidized poly (3,4- [6][7][8][9] and optimal operating conditions [10][11][12][13], 88 unlike it happens in the case of the widely studied Organic 89 Field Effect Transistors (OFETs) [14]. 90 Among the studies presented so far, our attention has 91 been attracted by two factors that can influence the OECT 92 response.…”