Photovoltaics is a central pillar of the energy supply of the future, as the most recent study by Fraunhofer ISE on the development of the German energy system confirms. For 40 years, Fraunhofer ISE has made an important contribution to increasing the efficiency of solar cells and the  reliability of PV modules and power plants, as well as further developing sustainable and cost-effective production processes for cells and modules. It is a research partner for the European solar industry along the entire PV value chain. Today, solar electricity is the least expensive form of energy in many parts of the world, but the potential of the technology is far from being exhausted.

With a view to future technological challenges, we are pleased that we can expand our infrastructure with the Center for High Efficiency Solar Cells. Our thanks for the financing of this new building – with 1000 m2 of the most modern laboratory areas and cleanroom equipment – go to  the German Federal Ministry for Education and Research (BMBF) and the State of Baden-Württemberg. Alongside the further development of silicon and III-V multi-junction solar cells, a focus of the new center is on the promising approach of Si-based tandem photovoltaics. This is  the combination of solar cell materials with different electronic properties such as III-V semiconductors, perovskites or silicon. Radiation from the broadband solar spectrum can thus be converted even more efficiently into electricity and the theoretical efficiency limit for conventional  solar cells of only a single solar cell material can be overcome. This results in the potential to save solar cell and module materials and thus contributes to the sustainability of photovoltaics. In addition, the area needed for PV expansion is reduced by the application of high-efficiency tandem solar cells. This applies particularly for their application in integrated photovoltaics, i.e. the utilization of PV modules in areas that are already used or built over, such as building envelopes and vehicle bodies. Multiplying installed PV by a factor of ten, which Germany needs to  meet its climate protection goals, demands efficient and sustainable technologies.

High-performance tandem cells place highest demands on series connection and encapsulation to produce durable and safe modules. We have adapted the industrial processing platforms in our Module-TEC to meet these demands. We have implemented different low-temperature connection technologies, which simultaneously eliminate most module-level power losses. 

Resource-saving production technology is playing an increasingly important role alongside increases in efficiency. The spin-off, HighLine Technology GmbH, originated from the photovoltaic production technology area. The goal of the start-up is to commercialize a new process that was developed at our institute, in which the metal contacts on the front surface of the solar cell are applied by a contactless dispensing procedure. This saves resources, increases the electricity yield and reduces costs. 

Beyond its technological development, Fraunhofer ISE is also active in reviving the European solar industry to retain the technological sovereignty of Europe. For example, the Institute is supporting the “Solar Europe Now” initiative, which demands recognition of solar energy as a key technology to achieve the goals of the European Green Deal.