Japanese scientists have discovered a ‘dream technology’ that could perfect solar panels

The research was conducted by scientists from Kyushu University in Japan, in collaboration with the German Johannes Gutenberg University in Mainz, and the findings were published in the Journal of the American Chemical Society, which is reported by TechRadar. Although the technology is still in its early stages, it represents a significant step in the search for more efficient ways of using solar energy.

How “dream technology” works

Keyč The innovations lie in a process called singlet fission, which the researchers described as a “dream technology” for converting light. In conventional solar cells, high-energy photons, such as those from the blue part of the spectrum, lose their excess energy as heat. Because of this, the maximum theoretical efficiency of standard silicon panels is limited to about 33 percent, a limit known as the Shockley-Queisser limit.

Singlet fission circumvents this problem by allowing one high-energy exciton (the energy carrier created by the absorption of a photon) to split into two lower-energy excitons. This theoretically doubles the number of usable energy carriers from the same photon.

“We have two main strategies for breaking through this limit,” explained Yoichi Sasaki, an associate professor at Kyushu University’s School of Engineering. “One is converting lower-energy infrared photons into higher-energy visible photons. The other, which we are investigating, is using singlet fission to generate two excitons from one photon.”

Capture of doubled energy

The main challenge so far has been how to effectively “capture” these doubled excitons before their energy is lost through other processes. The team solved that problem by developing a special chemical structure, the so-called “spin-flip” emitter. Riverč is about a complex based on molybdenum metal that is precisely tuned to selectively absorb and trap doubled excitons after they are created by the fission process.

“Energy can be easily ‘stolen’ by a mechanism called Förster resonance energy transfer (FRET) before it reaches multiplication,” said Sasaki. “That’s why we needed an energy acceptor that selectively captures the generated triplet excitons after fission.”

What does 130 percent efficiency mean?

It is key to understand that the 130 percent quantum yield does not refer to the total conversion of sunlight into electricity, which would violate the laws of physics. This percentage means that for every absorbed photon the system managed to generate 1.3 excitons. This proves that the energy multiplication process works and that the excess energy, which would otherwise be lost as heat, is successfully converted into additional charge carriers.

The experiments, conducted using tetracene-based materials in liquid solution, showed quantum yields ranging from just over 110 percent to about 130 percent. However, the technology is still far from practical application. The next key step for scientists is to integrate this system into the kind of material that could be used to make actual solar panels.

Broader context and future of solar energy

This research is part of the global race to increase the efficiency of solar technologies. While the “spin-flip” technology is still in its infancy, other advanced directions alreadyć show impressive progress:

Perovskite tandem ćcells: By combining a layer of perovskite with traditional silicon, laboratory prototypes of largerć have exceeded 33 percent efficiency, breaking the Shockley-Queisser limit.

Multijunction solar cells: They use multiple layers of semiconductors to absorb a wider spectrum of light and in laboratories reach an efficiency of more than 47 percent.

Global investments in renewable energy are also growing, and according to reports, they will reach 2.2 trillion dollars in 2025. Progress in efficiency is key to reducing costs and accelerating the energy transition. The scientists point out that their technology, apart from solar panels, could also be applied in other areas, such as OLED screens and lighting systems, where managing the behavior of excitons plays a key role in performance.