Characterization of Screen-Printed Organic Electrochemical Transistors to Detect Cations of Different Sizes.
A novel screen-printing fabrication method was used to prepare organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene) doped with polysterene sulfonate (PEDOT:PSS). Initially, three types of these screen-printed OECTs with a different channel and gate areas ratio were compared in terms of output characteristics, transfer characteristics, and current modulation in a phosphate buffered saline (PBS) solution. Results confirm that transistors with a gate electrode larger than the channel exhibit higher modulation. OECTs with this geometry were therefore chosen to investigate their ion-sensitive properties in aqueous solutions of cations of different sizes (sodium and rhodamine B). The effect of the gate electrode was additionally studied by comparing these all-PEDOT:PSS transistors with OECTs with the same geometry but with a non-polarizable metal gate (Ag). The operation of the all-PEDOT:PSS OECTs yields a response that is not dependent on a Na⁺ or rhodamine concentration. The weak modulation of these transistors can be explained assuming that PEDOT:PSS behaves like a supercapacitor. In contrast, the operation of Ag-Gate OECTs yields a response that is dependent on ion concentration due to the redox reaction taking place at the gate electrode with Cl-counter-ions. This indicates that, for cation detection, the response is maximized in OECTs with non-polarizable gate electrodes.
Group of Electronic Development and Printed Sensors (GEDPS), Centro de Reconocimiento Molecular y Desarrollo Tecnológico, Unidad Mixta UPV-UV, Valencia 46022, Spain. lcontat@ter.upv.es.
Laura
L
Contat-Rodrigo
Group of Electronic Development and Printed Sensors (GEDPS), Centro de Reconocimiento Molecular y Desarrollo Tecnológico, Unidad Mixta UPV-UV, Valencia 46022, Spain. cperezf@eln.upv.es.
Clara
C
Pérez-Fuster
Group of Electronic Development and Printed Sensors (GEDPS), Centro de Reconocimiento Molecular y Desarrollo Tecnológico, Unidad Mixta UPV-UV, Valencia 46022, Spain. jvlidon@eln.upv.es.
José Vicente
JV
Lidón-Roger
Dipartimento di Ingegneria Elettrica ed Elettronica, Università di Cagliari, Piazza d' Armi, Cagliari 09123, Italy. annalisa@diee.unica.it.
Annalisa
A
Bonfiglio
Group of Electronic Development and Printed Sensors (GEDPS), Centro de Reconocimiento Molecular y Desarrollo Tecnológico, Unidad Mixta UPV-UV, Valencia 46022, Spain. egarciab@eln.upv.es.
Eduardo
E
García-Breijo
PEDOT:PSS; large-size cations; organic electrochemical transistors; screen-printing
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