Photovoltaics and Wind Energy

At a glance

As part of the “Photovoltaics and Wind Energy” topic, Jülich researchers are investigating the next generations of solar cells and modules that will be significantly more efficient. They develop new materials and technologies and analyse the yield of the systems, investigate their life cycle, and plan pioneering recycling strategies.

Challenges

Under optimum conditions, 2.2 million solar systems currently supply around 60 gigawatts, or around 10 % of the electricity produced in Germany. By 2030, the installed photovoltaic capacity in Germany will have increased to 215 gigawatts and to 400 gigawatts by 2040. There is therefore great hope for solar energy. One of the biggest challenges is finding the perfect material. In terms of efficiency, silicon is currently hard to beat. However, it has some disadvantages: it is too rigid and heavy, and difficult to recycle.

Solutions

The Jülich researchers improve existing photovoltaic modules made of silicon and at the same time develop new efficient solar cell concepts using perovskite or organic materials.

The advantage of organic photovoltaic cells is that the modules can be flexible and also transparent; they can be integrated into windows and façades, used indoors or as roofing in fields. They also have a more favourable ecological footprint – the manufacturing processes are more environmentally friendly and the material is easier to recycle. The efficiency of such modules in the laboratory is now almost 20 %.

A combination of advanced silicon heterojunction and perovskite solar cells has even been able to achieve efficiencies of well over 30 %. Perovskite solar cells are inexpensive to print and incredibly efficient. However, perovskites are sensitive to moisture, oxygen, and high temperatures, which can lead to rapid degradation of the cells. Researchers at Jülich are optimizing the manufacturing processes and materials used to improve the lifespan and stability of this type of solar cell.

Reducing the energy demand involved in the production of conventional silicon solar cells and improving recycling are further goals of the Jülich researchers. To this end, a new process has been developed to deposit silicon from the gas phase onto a substrate at low temperatures. This is expected to reduce costs by 50 % and CO2 emissions by up to 75 %.

In another project, Jülich teams are testing alternative designs of silicon solar modules that do not require plastic and are therefore easier to recycle. The use of materials will also be reconsidered: silver as a contact material could become scarce worldwide due to the expected exponential increase in photovoltaics. The Jülich experts are investigating copper and graphene as alternatives.