University of Basel researchers develop new molecule to mimic photosynthesis

In Switzerland, a research team from the University of Basel has developed a new molecule modeled on plant photosynthesis: under the influence of light, it stores two positive and two negative charges at the same time. The aim is to convert sunlight into carbon-neutral fuels.

Plants use the energy of sunlight to convert CO2 into energy-rich sugar molecules. This process is called photosynthesis and is the foundation of virtually all life: animals and humans can “burn” the carbohydrates produced in this way again and use the energy stored within them. This once more produces carbon dioxide, closing the cycle.

This model could also be the key to environmentally friendly fuels, as researchers are working on imitating natural photosynthesis and using sunlight to produce high-energy compounds: solar fuels such as hydrogen, methanol and synthetic petrol. If burned, they would produce only as much carbon dioxide as was needed to produce the fuels. In other words, they would be carbon-neutral.

In the scientific journal Nature Chemistry, researchers have now reported on an important interim step toward achieving this vision of artificial photosynthesis: they have developed a special molecule that can store four charges simultaneously under light irradiation – two positive ones and two negative ones.

The intermediate storage of multiple charges is an important prerequisite for converting sunlight into chemical energy: the charges can be used to drive reactions – for example, to split water into hydrogen and oxygen.

The molecule consists of five parts that are linked in a series and each performs a specific task. One side of the molecule has two parts that release electrons and are positively charged in the process. Two on the other side pick up the electrons, which causes them to become negatively charged. In the middle, the chemists placed a component that captures sunlight and starts the reaction (electron transfer).