Optical method for making spatially and temporally resolved measurements of the hole concentration in organic electrochemical transistors

Electrochemical reduction and oxidation of PEDOT:PSS are used to modulate the channel current in organic electrochemical transistors (OECTs). In addition to changing PEDOT conductivity over more than 4 orders of magnitude, these redox reactions cause a shift in the PEDOT:PSS absorption spectrum. In this work we have used this shift in the absorption spectrum to make spatially and temporally resolved measurements of the redox state of PEDOT:PSS. By applying these measurements to the PEDOT:PSS in an OECT channel, we have shown that the redox state of the PEDOT:PSS is not constant along the channel during transistor operation. Furthermore, we have shown that the time constant of the optical transition is significantly larger near the transistor source than it is near the transistor drain. These results are not considered in existing models of the OECT transient response, and they may lead to a better understanding of geometry-performance relationships in OECTs.

[1]  E. Smela,et al.  Experimental Studies of Ion Transport in PPy(DBS) , 2009 .

[2]  S. Iannotta,et al.  Organic electrochemical transistors monitoring micelle formation , 2012 .

[3]  Yu Xuan,et al.  An all-polymer-air PEDOT battery , 2012 .

[4]  Kuo-Chuan Ho,et al.  Electrochemical characterization of the solvent-enhanced conductivity of poly(3,4-ethylenedioxythiophene) and its application in polymer solar cells , 2009 .

[5]  Manfred Lindau,et al.  Direct Measurement of Ion Mobility in a Conducting Polymer , 2013, Advanced materials.

[6]  Feng Yan,et al.  Fabrication of organic electrochemical transistor arrays for biosensing. , 2013, Biochimica et biophysica acta.

[7]  P. Leleux,et al.  In vivo recordings of brain activity using organic transistors , 2013, Nature Communications.

[8]  Feng Yan,et al.  Organic Electrochemical Transistors Integrated in Flexible Microfluidic Systems and Used for Label‐Free DNA Sensing , 2011, Advanced materials.

[9]  Yong-Young Noh,et al.  Downscaling of Organic Field‐Effect Transistors with a Polyelectrolyte Gate Insulator , 2008 .

[10]  George G. Malliaras,et al.  Measurement of Barrier Tissue Integrity with an Organic Electrochemical Transistor , 2012, Advanced materials.

[11]  A. Kornyshev,et al.  Double layer in ionic liquids: overscreening versus crowding. , 2010, Physical review letters.

[12]  Elisabeth Smela,et al.  Color and Volume Change in PPy(DBS) , 2009 .

[13]  M. Berggren,et al.  Electronic control of Ca2+ signalling in neuronal cells using an organic electronic ion pump. , 2007, Nature materials.

[14]  Yang Yang,et al.  On the mechanism of conductivity enhancement in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film through solvent treatment , 2004 .

[15]  Y. Kim,et al.  Highly Conductive PEDOT:PSS Electrode with Optimized Solvent and Thermal Post‐Treatment for ITO‐Free Organic Solar Cells , 2011 .

[16]  P. Leleux,et al.  High transconductance organic electrochemical transistors , 2013, Nature Communications.

[17]  George G. Malliaras,et al.  Steady‐State and Transient Behavior of Organic Electrochemical Transistors , 2007 .

[18]  M. Berggren,et al.  Detection of Glutamate and Acetylcholine with Organic Electrochemical Transistors Based on Conducting Polymer/Platinum Nanoparticle Composites , 2014, Advanced materials.