Commercial photovoltaic technologies have reached the terawatt (TW) range in terms of installed capacity worldwide. There will continue to be a very high demand for photovoltaic systems in the next few years, requiring scalable, cost-effective, and sustainable technologies to meet the ever-growing demand.
Silicon is currently the predominant material for solar cells in photovoltaic systems. However, there are limits to the efficiency of these cells. These limits can be overcome by using solar architectures made from different absorber materials, i.e. materials that absorb sunlight. Each material is designed to absorb a specific part of the solar radiation spectrum, meaning it is better at absorbing either short-wave or long-wave light. This allows the full spectrum of sunlight to be better utilized and the efficiency of the solar cell to be increased. If two or more solar cells made of different materials are combined, so-called tandem solar cells are obtained.
In this context, HIPOLE Jena is dedicated to perovskite solar cells. The name “perovskite” refers to a class of materials named after a characteristic crystal structure that can consist of a wide variety of elements.
The current focus is on optimizing the composition of the perovskite absorber to complement the absorption ranges of silicon while achieving exceptional intrinsic stability. Materials that can be applied over large areas and form selective and stable layers at the interfaces are particularly important. In this context, polymers in particular are a very interesting class of materials. During scaled processing, polymeric additives to so-called precursor inks can influence the flow properties (rheology) of the precursor solutions as well as the crystallization dynamics. This can result in the thin layers of perovskite material becoming more uniform, stable, and of higher quality.
Another area of application for polymers in photovoltaics is the encapsulation of the finished modules and cells. This refers to the coating of the solar cells with a protective material, which in the case of perovskite solar cells probably has to act both as a barrier against external influences such as moisture and mechanical stress as well as against the escape of possible degradation products such as toxic components such as lead.
HIPOLE Jena offers a unique opportunity to bring together the research environments of HZB and FSU Jena to produce high-performance single- and multilayer perovskite devices on small and large areas based on the design and synthesis of functional polymers.