An international group of researchers has, for the first time in history, achieved quantum efficiency in solar cells exceeding 100%. In their experiment, they reached a quantum yield of 130%. The results were published in the journal Journal of the American Chemical Society.

What It Means to “Exceed the Limit”

Conventional silicon solar panels are limited by the so-called Shockley–Queisser limit, according to which their maximum theoretical efficiency is about 33%. Much of the energy from sunlight is lost as heat.

Scientists have long been searching for ways to overcome this fundamental limitation. One of the most promising approaches is a process known as singlet fission. In this process, the energy of a single absorbed photon splits into two parts, producing two excited states (excitons) instead of just one.

How 130% Was Achieved

The team, led by chemist Eiichi Sasaki from Kyushu University, used the organic molecule tetracene, which efficiently splits photon energy. However, the main problem in earlier studies was that the resulting excitons lost energy too quickly and could not be effectively utilized.

The solution was to add molybdenum compounds. This metal acted as a “spin-converting emitter,” effectively capturing and holding excitons after splitting, preventing their loss.

As a result of the experiment, each absorbed photon produced an average of 1.3 excited states — corresponding to a quantum yield of 130%.

Eiichi Sasaki explained that there are two main ways to overcome this limit: one is to convert infrared radiation into visible light, and the other is to use singlet fission to generate two excitons from a single photon.

What Comes Next

For now, the technology remains at an early stage: all experiments were conducted in a liquid medium. The next major step will be transitioning to solid materials that can be integrated into real solar panels. Researchers also need to solve the challenge of retaining energy long enough for it to be efficiently converted into electricity.

Despite this, the study demonstrates the fundamental possibility of overcoming long-standing efficiency limits in solar energy technology.

In Brief

Scientists have exceeded the Shockley–Queisser limit for the first time, achieving a quantum efficiency of 130% in solar cells. By using singlet fission in tetracene molecules and adding molybdenum compounds to retain excitons, researchers produced an average of 1.3 excited states from a single photon. Although the technology is still at the laboratory stage, it opens a path toward significantly increasing the efficiency of solar panels in the future and could accelerate the development of renewable energy. The study was published in the Journal of the American Chemical Society.