Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Final Activity Report Summary - BIMORE (Bio-inspired Molecular Optoelectronics)

The project has investigated the elementary steps of highly efficient charge and energy transfer processes in biological materials, in order to transfer the function principles to artificial optoelectronic devices like, ultradense computer memories or highly efficient solar cells or light emitters. To accomplish these goals, BIMORE comprised 9 research institutions from 8 different countries, spanning the whole continent from Madrid (Spain) to Wroclaw (Poland) and from Odense (Denmark) to Haifa (Israel).

At the University of Glasgow (UK), light harvesting purple bacteria were grown, and the light harvesting complexes isolated and stabilised so that CNR-INFM (Milan, Italy) could study them using femtosecond spectroscopy, which is like making snapshots with an extremely fast flashlight. With this method, we could observe in which time the light energy "hops" from one complex to the other, until it reaches the "reaction centre", where the light energy is converted into biochemical energy for the bacterium. We could even observe that the light energy sometimes "hops back" to where it came from, and we understood under which conditions this is an advantage for the bacterium. These results show how energy transfer can be actively managed to optimise optoelectronic efficiencies. Our partners from Wroclaw (Poland) are experts in photochromic molecules.

Using light of the right colour, these molecules can be "switched" between two stable forms with different properties: the colour is strongly different, hence the name "photochromism", but also other properties change so that e.g. an electrical current can be controlled by irradiation of light. In BIMORE, the Wroclaw University of Technology collaborated with CNR-ISMN in Bologna, Italy, who are well-known for their work on light emitting transistors (LET), to develop an LET with a layer of photochromic molecules that showed favourable switching properties. Other approaches for optoelectronic switching are developed in collaboration with the Czech Academy of Sciences in Prague (CZ). Memory and logics devices in semiconductor industry are continuously scaled down to make them faster. The extreme case of miniaturisation is reached when the active "switch" consists only of a single molecule. Therefore it becomes important to understand how a current is passed through a single molecule that bridges two gold electrodes. Our industrial partner IBM-ZRL Zürich, inventors of the scanning tunnelling microscope (STM), applied an STM in the liquid phase to measure currents through single molecules that have been synthesised by Southern Denmark University (Odense, Denmark), experts in supramolecular synthesis. At the same time, the Autonomous University of Madrid, Spain, applies Quantum Chemistry to predict what IBM in Zurich is going to measure. They basically tell a super computer the positions of the atoms in the molecule and in the two gold contacts, and then calculate the transfer of electrons through the molecule using a model that they and others developed. If calculation and measurement agree, then probably the model is correct, and we can say that we have understood the conduction process.

Since in BIMORE, molecules are synthesised according to the results of the collaborations, this is a very good opportunity to really test the conduction model. BIMORE has produced a series of important publications, that have been cited already nearly 300 times in a short time. But scientific excellence is not the only quality of BIMORE. We gave the same priority to a strong development of complementary skills, dedicating two events entirely to them: One Summer School in the Scottish Highlands was concerned with leadership skills, such as, leading a research group, writing grant applications, giving an interview on TV. On the "Industrial Workshop", organised by IBM-ZRL, we learned how to combine research excellence with commercial success. BIMORE was also strongly present on events like, the European Researchers' Nights, to explain our approach, and the importance of international collaboration, to the public.

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