Ambipolar Charge Transport in Organic Semiconductors and Devices
Lead Research Organisation:
Imperial College London
Department Name: Physics
Abstract
Recent years have seen tremendous advances in the area of organic electronics mainly motivated by their emerging applications in electronic devices. A very important electronic device that is in the heart of today's microelectronic circuits is the transistor since it represents the building block of all everyday electronics. Very recently, organic based transistors also made their debut in a number of electronic devices and can be arguably viewed as possible alternatives to silicon-based devices in a range of low-cost and high-volume applications.Although recent progress is impressive, use of organic transistors in practical applications is hampered because the minimum requirements (speed, power-dissipation, cost) presently cannot be meet. The proposed work addresses these specific problems using an entirely different approach. We will study the electronic properties of organic semiconductors that are capable of transporting both electrons and holes. These are the so-called ambipolar organic semiconductors. During this fellowship we will develop and advance the knowledge on ambipolar transport in organic semiconductors but we will also exploit and assess various technologically relevant phenomena.We will first study ambipolar transport in a number of known ambipolar organic semiconductors through a combination of electrical, structural, chemical and spectroscopic measurements. Understanding the key electronic properties of these materials is essential for the development of improved or new semiconductors that will be subsequently synthesized through collaborations with various chemistry groups. Using the obtained knowledge, we will demonstrate ambipolar organic transistors and, initially, basic logic circuits like voltage inverters. New applications such as light-emitting transistors and sensors are expected to arise as a result of this work. Moreover, understanding ambipolar transport in organic materials is of basic scientific interest and is expected to benefit other scientific disciplines including chemistry and material science.
Organisations
People |
ORCID iD |
Thomas Anthopoulos (Principal Investigator) |
Publications
Anthopoulos T
(2007)
Electro-optical circuits based on light-sensing ambipolar organic field-effect transistors
in Applied Physics Letters
Bashir A
(2009)
High-Performance Zinc Oxide Transistors and Circuits Fabricated by Spray Pyrolysis in Ambient Atmosphere
in Advanced Materials
Campoy-Quiles M
(2008)
Morphology evolution via self-organization and lateral and vertical diffusion in polymer:fullerene solar cell blends.
in Nature materials
Hamilton R
(2009)
High-Performance Polymer-Small Molecule Blend Organic Transistors
in Advanced Materials
Smith J
(2010)
The Influence of Film Morphology in High-Mobility Small-Molecule:Polymer Blend Organic Transistors
in Advanced Functional Materials
Smith J
(2011)
Percolation behaviour in high mobility p-channel polymer/small-molecule blend organic field-effect transistors
in Organic Electronics
Wöbkenberg P
(2008)
Low-voltage organic transistors based on solution processed semiconductors and self-assembled monolayer gate dielectrics
in Applied Physics Letters
Wöbkenberg P
(2010)
TiO 2 thin-film transistors fabricated by spray pyrolysis
in Applied Physics Letters
Title | IMPROVED OXIDE-BASED FIELD-EFFECT TRANSISTORS |
Description | A field-effect transistor comprising: a source region; a drain region; a semiconductor layer disposed between the source and drain regions; a gate region; and a dielectric region disposed between the semiconductor layer and the gate region; wherein the semiconductor layer comprises a titanium dioxide film. The transistor may be light sensing, gas- or bio-sensing, or used in a visual display or in electronic circuits. Also provided is a method of forming a field-effect transistor comprising: forming a dielectric layer adjacent a gate; forming a source region and a drain region; and forming a semiconductor layer on the dielectric layer, the semiconductor layer comprising titanium dioxide. The titanium dioxide semiconductor layer may be deposited by spray pyrolysis, or alternatively mesoporous TiO2 films of nanocrystalline morphology may be formed by spin coating, doctor-blading or screen-printing techniques. |
IP Reference | WO2008129238 |
Protection | Patent application published |
Year Protection Granted | 2008 |
Licensed | No |
Impact | None |
Title | IMPROVEMENTS IN ORGANIC FIELD-EFFECT TRANSISTORS |
Description | An organic field-effect transistor comprising: a source region; a drain region; one or more organic semiconductor layers disposed between the source and drain regions; a gate region; and a dielectric region disposed between the organic semiconductor layer(s) and the gate region; wherein the composition of the organic semiconductor layer(s) is such as to transport both electrons and holes, with the mobility of the holes being substantially equal to the mobility of the electrons such that the transistor substantially exhibits ambipolarity in its transfer characteristics. The organic field-effect transistor is preferably a light-sensing organic field-effect transistor. Numerous modifications to the composition and structure of organic field-effect transistors are also disclosed, as are examples of electro-optical switches, electro-optical logic circuits and image sensing arrays. |
IP Reference | WO2008122778 |
Protection | Patent application published |
Year Protection Granted | 2008 |
Licensed | No |
Impact | None |