Its crucial function is to drive electrical signals utilising electrical signals in television sets, telephones, PCs and other devices. The smaller the circuits with which the signals are conducted, the faster the data processing.
At the University of Bayreuth, a research team centred around Prof. Dr. Jürgen Köhler, Dr. Martti Pärs and Prof. Dr. Mukundan Thelakkat has now demonstrated the amplifying function of an optical transistor. The point: in this transistor, light substitutes electricity. Light signals are driven by light signals.
In the recent online edition of the journal "Angewandte Chemie International Edition", the Bayreuth scientists introduce their discovery. Dr. Martti Pärs, a young physicist, made a particularly noteworthy contribution to the research. The results that have now been published evolved from the close co-operation between Experimental Physics and Macromolecular Chemistry within the Bayreuth campus. The results are the foundation of a completely new generation of transistors. The DFG supports the research in this area within the framework of the research training group "Photophysics of synthetic and biological multichromophor systems".
Another benefit: several optical "mini transistors" can be assembled to become a larger and even more powerful transistor because light signals, as opposed to electrical signals, do not interfere with each other. Therefore a multitude of data is processed simultaneously within a tiny space. Finally, any optical transistor regardless of size is superior relating to one aspect: all signals are processed at the speed of light – to be faster is not possible.Physical details:
At the opposite ends of the DCP molecules, the Bayreuth researchers have attached two organic chromophores, belonging to the perylene bisimides (PBI) group. PBI molecules are known for their ability to fluoresce strongly. This is always the case when a PBI molecule absorbs light energy and emits it.
A PBI molecule that is attached like an arm to a DCP molecule fluoresces with varying intensity – depending on whether the ring in the molecular switch is open or closed. When it is closed, the DCP is at a relatively low energy level. Therefore the PBI transfers the greatest part of its absorbed light energy to the DCP. The DCP dissipates light energy without fluorescence. In this case, the PBI weakly fluoresces. However, when the ring in the DCP is open, we observe the opposite. The DCP is at such a high energy level that the PBI is unable to pass on light energy to the DCP. Instead, it fully emits the absorbed light energy. The PBI is strongly fluorescent.
Further research challenges
Based on the above research results, a future vision of a new generation of transistors has emerged. For this vision to be realised one day, further research is necessary. For instance, it seems as if the fluorescent PBI molecules fade during longer periods of time. Consequently, their illumination power weakens. It is worthwhile to examine this effect more closely. A further observation of test conditions used so far is that it takes a relatively long period of time for the rings to open and close for a large number of DCP molecules. As a result, the gaps between the light signals driven by this process are rather large. The Bayreuth research team is therefore striving for a solution in order to minimise these periods of time.
Publication:Martti Pärs, Christiane C. Hofmann, Katja Willinger, Peter Bauer,
Christian Wißler | Universität Bayreuth
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy