05/18/2012

Julius-Maximilians-Universität Würzburg

Light and matter

Chemists and physicists are collaborating within a new research group at the University of Würzburg. Their stated objective is to enable the manufacture of new materials with customized properties. The German Research Foundation (DFG) is funding the project.

Is this what the energy source of the future will look like? Specially synthesized molecules split water into its components, hydrogen and oxygen, with the help of sunlight. The plan is for this process, which occurs in nature as “photosynthesis”, to be replicated in the laboratory to free the world from its dependency on fossil fuels. This artificial photosynthesis should supply mankind with a virtually inexhaustible and clean energy carrier.

Unfortunately, the dream of artificial photosynthesis as an energy supplier on a grand scale is still a long way off becoming a reality. Scientists have yet to acquire the necessary knowledge concerning the fundamental processes inside potential hydrogen producers. However, a new research group at the University of Würzburg is about to start work on this, bringing together scientists from various branches of physics and chemistry. Its spokesman is Professor Tobias Brixner, Chairman of the Department of Physical Chemistry I. The German Research Foundation (DFG) will be providing around EUR 2.3 million in funding for the project over the next three years.

New materials with specific properties

Molecular aggregates and their reactions to light will be the main focus of the Würzburg research group. “We will examine the interaction between light and matter with a view to understanding and controlling the dynamic processes and optical phenomena,” says Brixner. It is hoped that their findings will enable the scientists to customize new materials with specific properties.

Of course, facilitating the breakthrough of artificial photosynthesis will be just one of the goals with these new materials. Extremely energy-efficient light sources, tap-proof encryption technology, super-fast quantum computers, effective photovoltaic elements, nano-components that can repair themselves: these will all be conceivable once the fundamental processes in the molecular aggregates have been clarified and understood.

Research on molecular aggregates

Molecular aggregates: chemists understand these as the smallest building blocks in macroscopic systems such as liquids, solutions, or crystals. Inside these, molecules are arranged in specific structures with strong or weak links binding them. The diverse interactions between the individual blocks determine what happens inside the aggregates when light falls on them.

“What makes molecular aggregates so special and therefore appealing compared, for example, to inorganic solids is the fact that the properties of these molecular ‘basic building blocks’ can be varied deliberately,” explains Brixner. Changes at the microscopic level result in changes on a macroscopic scale as well. Though, the exact processes are still unknown. “In the past, although scientists went to great lengths examining countless molecules optically, there was generally no systematic variation of aggregates,” says Brixner. In many cases, therefore, current knowledge is inadequate for a prediction of the properties of a complex system based on the properties of the underlying molecular building blocks.

Better understanding of internal processes

This is where the work of the Würzburg research group will begin: the group will spend the next three years closely studying the interactions between light and matter in molecular aggregates. “Once we are familiar with the fundamental rules of the interactions, it should be possible to produce a new generation of materials that exceed those we have today,” states Brixner.

The Würzburg research group possesses the knowledge and technology required for this research. Its members come from the fields of theoretical, physical, and organic chemistry as well as experimental physics; they have the necessary expertise in all the requisite research methods and in the respective equipment – ranging from spectroscopy to photoconductivity measurement. The bundling of available experimental and theoretical resources will enable “unique cooperative research in the area of light-matter interaction”.

The members of the research group are as follows:

from Physical and Theoretical Chemistry:
• Prof. Dr. Tobias Brixner
• Prof. Dr. Volker Engel
• Prof. Dr. Bernd Engels

from Organic Chemistry:
• Prof. Dr. Christoph Lambert
• Prof. Dr. Frank Würthner

from Experimental Physics:
• Prof. Dr. Vladimir Dyakonov
• PD Dr. Carsten Deibel
• Prof. Dr. Jens Pflaum

as well as the following associated junior researchers:
• Dr. Florian Beuerle
• Dr. Gustavo Fernández
• Dr. Patrick Nürnberger

The German Research Foundation (DFG) has decided to set up a total of six new research groups and one clinical research group. These research consortia should provide scientists with the opportunity to “address current and urgent issues in their fields and to develop new methods for tackling them”, according to a DFG press release. The foundation currently funds 191 research groups.

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