Solar Energy Transformed Using Artificial Leaf
An international team of researchers has changed chlorophyll from an alga so that it resembles the immensely efficient light antennae of bacteria. The team then managed to determine the structure of these light antennae. This is the first measure to transforming sunlight into energy using an artificial leaf. The researchers will be creating an article on their research findings in the online Early Edition of the PNAS journal.
They are the subject of dreams: artificial forests at nano scale. Or pavements and motorways where gaps in the surface are covered with pigment molecules that collect sunlight and convert it into fuel and other forms of – clean – energy. But before this can happen, artificial photosynthesis systems first have to be developed that work both quickly and effectively.
Two things are required to generate fuel from sunlight: an antenna that harvests light, and a light-driven catalyst. The article in PNAS is about the first of these: the antenna.
The most rapid light harvesters are to be discovered in nature: in green leaves, algae and bacteria. The light antennae of bacteria – chlorosomes – are the fastest of all. They have to be capable of harvesting minimal quantities of light particles in highly unfavorable light conditions, such as deep in the sea. These chlorosomes are constituted of chlorophyll molecules. The art is to imitate these systems very accurately.
German colleagues from the University of Würzburg in Huub de Groot’s team modified chlorophylls from the alga Spirulina, such that they resembled the pigments of bacteria. De Groot’s Leiden group then studied the structure of these semi-synthetic light antennae.
Nanotechnology and supramolecular systems are becoming highly significant, 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.
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.”
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 permitted the researchers to explain how the antennae were able to operate so quickly and so effectively.
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Very interesting report.The discovery of the light antenaes and creating the practical usage technologies may hitch, impell stranded Solar energy ship. The existing Solar energy technologies are not in progress for a long time and nobody knows who are taking pains to stop a force of progress and to keep, embed “traditional”enerhy usage in all spheres of our life ?
Very interesting report.The discovery of the light antenaes and creating the practical usage modes may raise the efficency of the existing Solar energy technologies .