translating-extracellular-electron-transfer-activities-with-organic

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

Extracellular electron transfer (EET) is a process through which certain microorganisms can transfer electrons across their cell membranes to external ...

The University of Texas at Austin

To scale down thin-film transistor (TFT) channel lengths for accessing higher levels of speed and performance, a redesign of the basic device structure is necessary. With nanospike-shaped electrodes, field-emission effects can be used to assist charge injection from the electrodes in sub-200-nm channel length amorphous oxide and organic TFTs. These designs result in the formation of charge nanoribbons at low gate biases that greatly improve subthreshold and turn-off characteristics. A design paradigm in which the gate electric field can be less than the source-drain field is proposed and demonstrated. By combining small channel lengths and thick gate dielectrics, this approach is also shown to be a promising solution for boosting TFT performance through charge focusing and charge nanoribbon formation in flexible/printed electronics applications.

Nanospike electrodes and charge nanoribbons: A new design for nanoscale thin-film transistors.

Organic electrochemical transistors (OECTs) are ideal devices for translating biological signals into electrical readouts and have applications in bioelectronics, biosensing, and neuromorphic computing. Despite their potential, developing programmable and modular methods for living systems to interface with OECTs has proven challenging. Here we describe hybrid OECTs containing the model electroactive bacterium  that enable the transduction of biological computations to electrical responses. Specifically, we fabricated planar p-type OECTs and demonstrated that channel de-doping is driven by extracellular electron transfer (EET) from . Leveraging this mechanistic understanding and our ability to control EET flux via transcriptional regulation, we used plasmid-based Boolean logic gates to translate biological computation into current changes within the OECT. Finally, we demonstrated EET-driven changes to OECT synaptic plasticity. This work enables fundamental EET studies and OECT-based biosensing and biocomputing systems with genetically controllable and modular design elements.

A Hybrid Transistor with Transcriptionally Controlled Computation and Plasticity.

A device architecture based on heterostructure WSe/organic semiconductor field-effect transistors (FETs) is demonstrated in which ambipolar conduction is virtually eliminated, resulting in essentially unipolar FETs realized from an ambipolar semiconductor. For p-channel FETs, an electron-accepting organic semiconductor such as hexadecafluorocopperphthalocyanine (FCuPc) is used to form a heterolayer on top of WSe to effectively trap any undesirable electron currents. For n-channel FETs, a hole-accepting organic semiconductor such as pentacene is used to reduce the hole currents without affecting the electron currents. Off-currents are reduced in FETs with heterolayers compared to WSe FETs without organic heterolayers, which will decrease static power dissipation in complementary circuits. In all FETs reported in this work, the organic heterolayers cover only part of the channel, which results in more effective trapping of the carrier type that must be reduced. This device design approach can be effectively combined with p-type doping and contact metal engineering to improve WSe based FETs and circuits. Complementary inverters realized with such heterostructured FETs exhibit excellent transfer characteristics. This design approach is also applicable to other ambipolar semiconductors besides WSe.

Yuchen Zhou

Department of Electrical and Computer Engineering,
Microelectronics Research Center

The University of Texas at Austin

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

Yuchen Zhou

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Electrical and Computer Engineering,Microelectronics Research Center

The University of Texas at Austin

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

Department of Electrical and Computer Engineering,
Microelectronics Research Center