Artificial photosynthesis

Article By:

Weare, Walter W. Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.

Frei, Heinz Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.

Last reviewed:2009

DOI:https://doi.org/10.1036/1097-8542.YB090126

The harnessing of sunlight in the form of a fuel through the direct conversion of visible photons to chemical energy by a synthetic device made of inorganic, organic, or hybrid materials is an attractive goal. Such artificial photosynthetic devices, in contrast to the synthesis of biofuels via plants, would not be restricted by the availability of arable land. Moreover, many efficiency limitations of biological photosynthesis, such as the tenfold attenuation of the photon conversion yield at high solar light intensity (at noon) by light regulation mechanisms acting to prevent photooxidative damage of plant cell material, would be absent in technological systems. Proof of concept for the efficient conversion of sunlight to hydrogen and oxygen by water splitting was demonstrated in a single integrated device by John Turner of the National Renewable Energy Laboratory in the late 1990s. The device is a monolithic, multilayer semiconductor material capable of splitting water with a conversion efficiency in excess of 10% for sunlight to chemical energy of hydrogen (H₂). However, the material degrades under use within days, is made of elements that are not sufficiently abundant, and employs fabrication processes akin to making a computer microchip, all of which make the device unsuitable for manufacturing on the scale needed for global fuel generation. Therefore, the most pressing need for making practical artificial solar fuel generators a reality is to develop robust systems that are made from abundant elemental components using scalable processes.

The content above is only an excerpt.