Related Experiment Video
Updated: May 13, 2026
08:43
Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors
Published on: November 7, 2016
Anomalous pressure effect in heteroacene organic field-effect transistors
1ISIR, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan. ksakai@sanken.osaka-u.ac.jp
Physical Review Letters
|March 19, 2013
Summary
Organic semiconductors show unusual conductivity changes under pressure. Unlike typical materials, their mobility can decrease with increasing pressure, a phenomenon linked to molecular rearrangements.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Organic Electronics
Background:
- Organic field-effect transistors (OFETs) are crucial for flexible electronics.
- Understanding charge transport mechanisms in organic semiconductors under external stimuli is vital for device optimization.
- Heteroacene molecules present unique structural and electronic properties.
Purpose of the Study:
- To investigate the pressure-dependent conductivity of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene single-crystal organic field-effect transistors.
- To analyze the anomalous pressure response of charge carrier mobility in these organic semiconductor devices.
- To elucidate the relationship between molecular structure, orientation, and electrical properties under hydrostatic pressure.
Main Methods:
- Fabrication and characterization of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene single-crystal organic field-effect transistors.
- Measurement of conductivity and charge carrier mobility under varying hydrostatic pressures.
- X-ray diffraction experiments to analyze crystal structure changes under pressure.
Main Results:
- Observed anomalous pressure-dependent conductivity along the a and b crystallographic axes.
- Demonstrated nonmonotonic and gigantic pressure dependence of mobility (μ), including negative pressure coefficients (dμ/dP).
- Correlated the anomalous behavior with pressure-induced on-site molecular orientation and displacement.
Conclusions:
- The study reveals a unique, nonmonotonic pressure response in heteroacene organic semiconductors.
- Molecular rearrangements and orientation changes are identified as key factors governing this anomalous behavior.
- Findings provide insights for designing organic electronic materials with tailored pressure sensitivity.
Related Concept Videos
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...
01:29Field Effect Transistor
Field-effect transistors (FETs) are integral to electronic circuits and distinguished by their three-terminal setup: the gate, drain, and source. These transistors operate as unipolar devices, which utilize either electrons or holes as charge carriers, in contrast to bipolar transistors, which use both types of carriers. The primary function of the FET is to modulate the flow of these carriers from the source to the drain through a channel. The voltage difference between the gate and source...
01:16Biasing of P-N Junction
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
01:22Biasing of FET
Biasing a Junction Field Effect Transistor (JFET) is crucial for setting operational parameters and ensuring efficient functioning in electronic circuits. JFETs are characterized by using a single carrier type in N-channel or P-channel configurations, where the channel is surrounded by PN junctions. These junctions are central to the device's ability to control current flow.
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
01:27Biasing of Metal-Semiconductor Junctions
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
01:22MOSFET: Enhancement Mode
Enhancement-mode MOSFETs are pivotal components in electronics, distinguished by their capacity to act as highly efficient switches. They are part of the larger family of metal-oxide Semiconductor Field-Effect Transistors (MOSFETs). They are available in two types: p-channel and n-channel, each tailored to specific polarity operations.
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no current...
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no current...