Converting light into energy with ‘artificial leaf’ one step closer

As an efficient, natural means of capturing solar energy, photosynthesis is hard to beat. But it’s also proving extremely difficult to duplicate. That’s why researchers at Leiden University in the Netherlands are very excited at having built a light-harvesting antenna using the chlorophyll of the alga Spirulina: they’re now halfway towards the artificial leaf.

Before sunlight can be converted into energy, it must first be harvested. The best light-capturers in nature are the chlorosomes of bacteria, which can harvest light particles in even the worst conditions, such as at the bottom of the ocean. Professor Huub de Groot’s team worked out a way of imitating these chlorosomes in an interestingly back-to-front way.

First, using modified chlorophyll molecules from Spirulina, they assembled a semi-synthetic model that resembled a bacterial light antenna. Then, with x-ray diffraction and nuclear magnetic resonance (NMR), they were able to determine the exact molecular and supramolecular structure of their home-made light antenna. A case of make it first, figure out how it works later.

What they now have is a molecular blue-print that imitates the most efficient light-gatherer in nature. The next step is finding a way to convert that light into energy. Once that happens, the idea of artificial forests at a nano scale, producing clean energy from light, won’t seem so far away.