Swiss breakthrough in artificial photosynthesis

August 27, 2025

A research team at the University of Basel in Switzerland has created a groundbreaking molecule inspired by the natural process of photosynthesis. This innovation can simultaneously store two positive and two negative charges when exposed to light, a key step toward converting sunlight into carbon-neutral fuels such as hydrogen, methanol, and synthetic gasoline.

How photosynthesis inspired the research

In nature, plants absorb sunlight to transform carbon dioxide (CO₂) into energy-rich sugars, a process known as photosynthesis. These sugars fuel life on Earth, as animals and humans consume and metabolize them, releasing CO₂ back into the atmosphere and completing the cycle.

Researchers are now working to replicate this process artificially. If successful, artificial photosynthesis could produce renewable solar fuels that emit only the same amount of CO₂ required for their production—making them fully carbon-neutral and sustainable alternatives to fossil fuels.

A molecule with unique charge storage

In their study published in Nature Chemistry, Professor Oliver Wenger and doctoral researcher Mathis Brändlin unveiled a molecule that can hold four charges under light irradiation—two positive and two negative.

This ability is crucial, as storing multiple charges enables the conversion of solar energy into chemical energy. These charges can then be directed to power vital reactions such as splitting water into hydrogen and oxygen, a central process for clean hydrogen fuel production.

How the molecule works

 The molecule is made of five interconnected components, each with a dedicated role:

• Two donor units release electrons, becoming positively charged.
• Two acceptor units capture electrons, becoming negatively charged.
• A central photosensitive unit absorbs light and initiates the electron transfer process.

By exposing the molecule to two successive flashes of light, the team successfully generated two positive and two negative charges.

Efficient even in low light

Unlike earlier experiments that required intense laser beams, the Basel team’s molecule functions with much weaker light sources, close to the natural intensity of sunlight.

“The stepwise excitation lets us work with significantly dimmer light, moving much closer to real sunlight,” explains Brändlin. Importantly, the charges in the molecule remain stable long enough to drive additional chemical reactions—making the system practical for future applications.

A key step toward artificial photosynthesis

While this molecule does not yet constitute a complete artificial photosynthesis system, it represents a vital milestone in sustainable energy research.

“We’ve identified and implemented an essential piece of the puzzle,” says Professor Wenger. “These findings deepen our understanding of electron transfers, which are at the heart of artificial photosynthesis.”

Toward a sustainable energy future

The University of Basel team’s discovery brings scientists closer to developing scalable solar-to-fuel technologies. With continued advances, artificial photosynthesis could become a transformative solution for clean energy, offering carbon-neutral fuels that help fight climate change and reduce dependence on fossil resources.

“We hope our work opens new pathways toward a sustainable energy future,” concludes Wenger.