Organic solar cells are on the verge of a breakthrough

When Carl Leo looks out at the rows of houses, the first thing he thinks about is potential. "You have to have solar on almost every roof," he said. But the physics professor at Technische Universitat Dresden also knows how hard it is.

The roof has a curve or Angle, and the Windows cannot be obscured. "That makes a lot of valuable space unusable," explains Leo, one of the leading scholars in solar cell technology.

The rules for installing solar equipment in new buildings in all German federal states are now being tightened to varying degrees due to the country's plan to switch to green electricity by 2035. Germany's "renewable energy Law" stipulates that Germany's cumulative installed photovoltaic capacity in 2030 should reach 215 gigawatts. Therefore, according to the PV strategic plan of the Federal Ministry of Economic Affairs, new PV capacity must be tripled from a full 7 gigawatts in 2022 to 22 gigawatts per year.

Achieving these goals requires more space. Scientists have developed a new type of solar panel that promises to solve this problem: organic solar cells. Thin, bendable organic solar cells are made not of silicon but of hydrocarbons. The possibilities are endless.

The static characteristics of curved roofs, bodies and aircraft wings are not yet suitable for the installation of traditional silicon components. The new flexible solar cells can not only be used in these places, but can even be installed on glass curtain walls and Windows, because they only absorb part of the visible light.

The low conversion rate is the main reason why organic solar cells with many advantages have not been widely used. Conventional silicon modules can convert 20% of solar energy into electricity, while organic solar cells have a conversion rate of only 9%.

The region can produce solar cells at a lower cost and also has large quantities of rare earths needed to produce traditional solar cells. Organic solar cells do not require such raw materials. This new way of getting energy is expected to bring some of the solar industry back to Germany.

"In order to compete, we either have lower production costs or we have patents and technology," says Mr Leow. Organic batteries could be the answer. "We have the knowledge and practical basic patents in materials, components and manufacturing technology," he added.

Leau called for more research funding to accelerate Germany's development in the field. "We could do a lot more if research projects were better supported," he says.

Leo has been working on organic solar cells at the Technical University of Dresden since the 1990s. In addition to him, about 30 companies and dozens of research institutions from around the world are also conducting relevant research. In 2006, the physicist founded Heliatek with five other scientists from the Technical University of Dresden and the University of Ulm. The company has been mass-producing organic solar cells since 2019 and is the global market leader in this field.

The company counts Germany's E.ON Energy group among its customers, as well as South Korean technology giant Samsung and companies from France, Spain, Britain, Singapore and Japan. Guido Van Tatvek, director of Helia Technologies, says demand is growing particularly strongly from Southeast Asia.