A new transistor based on organic materials has been developed by scientists at Linköping University. It has the ability to learn, and is equipped with both short-term and long-term memory. The work is a major step on the way to creating technology that mimics the human brain.
Until now, brains have been unique in being able to create connections where there were none before. In a scientific article in Advanced Science, researchers from Linköping University describe a transistor that can create a new connection between an input and an output. They have incorporated the transistor into an electronic circuit that learns how to link a certain stimulus with an output signal, in the same way that a dog learns that the sound of a food bowl being prepared means that dinner is on the way.
A normal transistor acts as a valve that amplifies or dampens the output signal, depending on the characteristics of the input signal. In the organic electrochemical transistor that the researchers have developed, the channel in the transistor consists of an electropolymerised conducting polymer. The channel can be formed, grown or shrunk, or completely eliminated during operation. It can also be trained to react to a certain stimulus, a certain input signal, such that the transistor channel becomes more conductive and the output signal larger.
“It is the first time that real time formation of new electronic components is shown in neuromorphic devices”, says Simone Fabiano, principal investigator in organic nanoelectronics at the Laboratory of Organic Electronics, Campus Norrköping.
The channel is grown by increasing the degree of polymerisation of the material in the transistor channel, thereby increasing the number of polymer chains that conduct the signal. Alternatively, the material may be overoxidised (by applying a high voltage) and the channel becomes inactive. Temporary changes of the conductivity can also be achieved by doping or dedoping the material.
“We have shown that we can induce both short-term and permanent changes to how the transistor processes information, which is vital if one wants to mimic the ways that brain cells communicate with each other”, says Jennifer Gerasimov, postdoc in organic nanoelectronics and one of the authors of the article.
By changing the input signal, the strength of the transistor response can be modulated across a wide range, and connections can be created where none previously existed. This gives the transistor a behaviour that is comparable with that of the synapse, or the communication interface between two brain cells.
Hardware for machine learning
It is also a major step towards machine learning using organic electronics. Software-based artificial neural networks are currently used in machine learning to achieve what is known as “deep learning”. Software requires that the signals are transmitted between a huge number of nodes to simulate a single synapse, which takes considerable computing power and thus consumes considerable energy.
“We have developed hardware that does the same thing, using a single electronic component”, says Jennifer Gerasimov.
“Our organic electrochemical transistor can therefore carry out the work of thousands of normal transistors with an energy consumption that approaches the energy consumed when a human brain transmits signals between two cells”, confirms Simone Fabiano.
Newly developed monomer
The transistor channel has not been constructed using the most common polymer used in organic electronics, PEDOT, but instead using a polymer of a newly-developed monomer, ETE-S, produced by Roger Gabrielsson, who also works at the Laboratory of Organic Electronics and is one of the authors of the article. ETE-S has several unique properties that make it perfectly suited for this application – it forms sufficiently long polymer chains, is water-soluble while the polymer form is not, and it produces polymers with an intermediate level of doping. The polymer PETE-S is produced in its doped form with an intrinsic negative charge to balance the positive charge carriers (it is p-doped).
Learn more: Learning transistor mimics the brain
The Latest on: Organic electrochemical transistor
via Google News
The Latest on: Organic electrochemical transistor
- Ion buffering and interface charge enable high performance electronics with organic electrochemical transistorson July 10, 2019 at 2:11 am
Organic electrochemical transistors rely on ionic-electronic volumetric interaction to provide a seamless interface between biology and electronics with outstanding signal amplification. Despite their ...
- Look Out, Silicon: Bio-Organic/Compatible Transistors are Coming on Strongon June 3, 2019 at 1:44 pm
The transistor, which has relatively high transconductance and speed, can be used either as a single device or “microfabricated” to create the equivalent of integrated circuits. In their detailed ...
- Organic Bioelectronic Interfaces based on PEDOT:PSS films, microfibres and fibrillar hydrogelon May 27, 2019 at 5:00 pm
In this research, we developed organic bioelectronic interfaces based on highly ... PSS-incorporated hydrogel microfibers for single-strand wearable electrochemical transistors and 3-D neuronal ...
- Biocompatible Transistor Invented for New Deviceson March 28, 2019 at 2:41 am
A team led by Dion Khodagholy, assistant professor of electrical engineering at Columbia University’s engineering department, invented what’s called an internal-ion-gated organic electrochemical ...
- A New Ion-Drive Transistor Is Here to Interface With Your Brainon March 12, 2019 at 7:10 am
Scientists have been able to minimize some of those issues with organic electrochemical transistors, which rely on biocompatible molecules linked to each other to form a “channel” that allows signals ...
- Fast, flexible ionic transistors for bioelectronic deviceson February 27, 2019 at 2:30 pm
The internal-ion-gated organic electrochemical transistor (IGT) operates via mobile ions contained within a conducting polymer channel to enable both volumetric capacitance (ionic interactions ...
- Fast, flexible ionic transistors for bioelectronic deviceson February 27, 2019 at 12:43 pm
Researchers have developed the first biocompatible internal-ion-gated organic electrochemical transistor (IGT) that is fast enough to enable real-time signal sensing and stimulation of brain signals.
- Internal ion-gated organic electrochemical transistor: A building block for integrated bioelectronicson February 27, 2019 at 11:11 am
1 Department of Electrical Engineering, Columbia University, New York, NY 10027, USA. 2 Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA. 3 Institute for Genomic ...
- Novel organic transistor that mimics brain developed by scientistson February 6, 2019 at 1:34 am
A normal transistor acts as a valve that amplifies or dampens the output signal, depending on the characteristics of the input signal. In the organic electrochemical transistor that the researchers ...
- Neuromorphic Computing Breakthrough May Disrupt AIon February 5, 2019 at 4:00 pm
Gerasimov, Roger Gabrielsson, Robert Forchheimer, Eleni Stavrinidou, Daniel T. Simon, and Magnus Berggren created an organic electrochemical transistor (OECT) that can learn, form new connections ...
via Bing News