First step to converting solar energy using 'artifi...( Nanotechnology De Groot: ' Nanotec...)

De Groot: ' Nanotechnology and supramolecular systems are becoming increasingly important, but it is very difficult to determine their structure. So-called cartoons are frequently made that give a schematic indication of what their structure could be.'

De Groot and his colleagues successfully determined the detailed molecular and supramolecular structure of their artificial self-assembled light antennae. They did this using a combination of solid state NMR and X-ray diffraction (see attachment). X-ray diffraction enabled them to determine the overall structure and NMR allowed them to penetrate deeply into the molecules.

Stacking of molecules

De Groot: 'We already knew that the light antennae in bacteria form a structure rather like the annual rings of a tree trunk. The molecules in these semi-synthetic antennae seem to stack in a different way; they are flat. But this, too, is one of four ways we had thought in advance were possible.

New approach

The researchers still have to determine how the light antennae of modified Spirulina chlorophylls work in practice. De Groot: 'This is a completely new approach in this field.'

The new insights are coming in quick succession. Last month, De Groot, with an international team made up partly of different members, also reported a breakthrough in PNAS. In that article he showed how also with a combination of NMR and another technique, namely electron microscopy he had resolved the structure of the light antennae of the bacteria themselves. This allowed the researchers to explain how the antennae were able to function so quickly and so efficiently.

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