An All-Plastic Field-Effect Nanofluidic Diode Gated by a Conducting Polymer Layer

PÉREZ-MITTA, GONZALO; MARMISOLLÉ, WALDEMAR A.; TRAUTMANN, CHRISTINA; TOIMIL-MOLARES, MARÍA EUGENIA; AZZARONI, OMAR

ADVANCED MATERIALS

WILEY-V C H VERLAG GMBH

Año: 2017

0935-9648

Currently there is a growing interest in developing nanofluidic devices with the capacity to externally regulate the flow of different molecules within miniaturized integrated circuits. With the rise of nanofluidics starting approximately twenty years ago, large advances in the fabrication of devices that control ionic carriers have been achieved. [ , , , ] Nanofluidic devices may have similar functioning as biological ion channels that behave either as ionic resistor or diode.[ , ] Moreover, complex systems such as field-effect transistors and bipolar transistors have been fabricated with amazing technological applications in fields such as biosensing or surface sciences.[ , , , , ] For example, a device to sequence DNA strands based on nanopore resistors has recently been put on the market. [ ] These first advances can be compared to the progress in electron conduction reached by the semiconductor technologies.However, there is still a long way to achieve complete control over the transport of molecules in integrated ionic circuits. Ionic diodes are very promising because they regulate the selective transport of ions in a voltage dependent manner, with the selectivity easily to be detected by ionic current rectification in current-voltage measurements. [ ] Either cations or anions can be excluded as current carriers depending on the net surface charge of the nanofluidic structure. [ ]Several attempts have been made to modulate the response of ionic diodes in a manner that allows changing the magnitude and direction of this rectification at will. Until now, this has been effectively obtained only by specific chemical stimuli in solution, such as the pH. [ , , ] Aiming at implementing such nanofluidic devices in more complex designs, there is a strong interest in being able to modulate ionic currents by experimental inputs that are easier to control, such as voltage, light or temperature. [ ] In this regard, our group has already proven that the combination of solid-state polymer nanopores and electrochemically synthesised conductive polymers is a promising starting platform. [ ]Herein, we present the fabrication of a field-effect tunable ionic diode by implementing the chemically synthesized conducting polymer Poly(3,4-ethylenedioxothiophene) (PEDOT) upon a solid-state polymeric nanopore. The PEDOT layer enhances the rectification properties of the nanopore and most importantly, acts as a field-effect non-metallic gate electrode by changing its electrochemical state by applying different voltages. A strong reversion and modulation of the surface charge and consequently the rectification efficiency is observed.