Research into Light Harvesting Technology.
Plants have the natural ability to absorb photons from sunlight and use it as energy. They accomplish this with special molecules in their leaves called chlorophyll. For years, researchers have been trying to replicate this natural process.
So far, no man-made system has been successful in converting sunlight, which has low photon levels, into usable energy. The supply of fossil fuels continues to dwindle each year while energy demand is on the rise globally. It is now clear that there is need for alternative and sustainable solutions to this coming crisis.
Significance of Artificial Photosynthesis
Many technologies already available use energy from the sun may it be photovoltaic cells or thermal solar. However, they face a constraint when trying to transport them over the grid. The U.S. grid has many inefficiencies. Consequently, this makes it difficult to harness these technologies efficiently. Mimicking photosynthesis may be the answer. Plants are able to use light even at amazingly low intensity to generate energy for their cells.
How It Works
Scientists from the Tokyo Institute of Technology Japan, in collaboration with Toyota Central Research Labs, were the first to make a breakthrough in artificial light harvesting systems. The system uses man made leaves to trap light. They relay energy through a metal complex to feed a final energy receiver.
“It is difficult to make an efficient solar-energy converter using molecular devices such as so-called photocatalysts because the molecules are so small and solar light is so dilute,” explained Ishitami.
Such systems would require huge numbers of molecular devices, which are expensive and time-consuming to make. Introducing devices with the ability to harvest light into solar-energy conversion would be one possible solution.
However, the researchers were able to overcome this hurdle to develop a photon collection system that is more efficient. Ishitami and his team built a device that has 440 artificial leaves. The artificial leaves were connected to five interlinked rhenium metal sticks that transferred energy harvested to a central ruthenium sphere. Photons concentration was very efficient, first through the rhenium’s metal sticks and later into ruthenium sphere, with little loss of energy. The main challenge in developing artificial photosynthesis has always been efficient photon collection. The new system developed by the researchers is awesome because it allows accumulation of photons from a large area.
Many other researchers who are working on artificial photosynthesis were impressed by the work. They view this as a real breakthrough. However, Ishitami states that, although it is a positive move, there is still a lot of research that needs to be done. Research into artificial photosynthesis is not new. Italian photo chemist, Giacomo Ciamician first proposed the idea at a conference in 1912. He had a vision of a world powered by sunlight without the need for coal. However, the idea took long to gain traction since nobody really knew how it worked at a molecular level. With the renewed interest in alternative energy, a lot of scientists continue to make breakthroughs into the use of artificial photosynthesis. Maybe we could soon see serious funding and collaboration in this field that will one day replace the need for fossil fuels.
Gordon's expertise in the area of industrial energy efficiency and alternative energy. He is an experienced electrical engineer with a Masters degree in Alternative Energy technology. He is the co-founder of several renewable energy media sites including Solar Thermal Magazine.