First organic bipolar transistor developed at TU Dresden
The invention of the transistor in 1947 by Shockley, Bardeen and Brattain at Bell Laboratories ushered in the era of microelectronics and revolutionized our lives. First of all, so-called bipolar transistors were invented, in which negative and positive charge carriers contribute to current transport, unipolar field-effect transistors were added only later. The increase in performance due to the scaling of silicon electronics into the nanometer range has dramatically accelerated data processing. However, this very rigid technology is less suitable for new types of flexible electronic components, such as rollable television screens or for medical applications on or even in the body.
For such applications, transistors made of organic semiconductors, that is to say based on carbon, have been developed in recent years. Organic field effect transistors were introduced as early as 1986, but their performance still lags far behind silicon components.
A research group led by Prof. Karl Leo and Dr. Hans Kleemann at TU Dresden has now succeeded for the first time in demonstrating a highly efficient organic bipolar transistor. The use of highly ordered thin organic layers was crucial for this. This new technology is several times faster than previous organic transistors, and for the first time the components have reached gigahertz operating frequencies, or more than a billion switchings per second. Dr Shu-Jen Wang, who co-led the project with Dr Michael Sawatzki, explains: “The first realization of the organic bipolar transistor was a big challenge, because we had to create very high quality layers and new structures. However, the excellent component parameters reward these efforts! Professor Karl Leo adds: “We have been thinking about this device for 20 years and I am delighted that we have now been able to demonstrate it with the new highly ordered layers. The organic bipolar transistor and its potential open completely new perspectives for organic electronics, as they also enable demanding tasks in data processing and transmission. Possible future applications are, for example, smart patches equipped with sensors that process sensor data locally and communicate wirelessly with the outside.
„Organic Bipolar Transistors”, Shu-Jen Wang, Michael Sawatzki, Ghader Darbandy, Felix Talnack, Jörn Vahland, Marc Malfois, Alexander Kloes, Stefan Mannsfeld, Hans Kleemann, Karl Leo. Nature, June 22, 2022. https://www.nature.com/articles/s41586-022-04837-4