Transparent organic solar cells

Moving global energy consumption away from fossil fuels requires innovative renewable energy solutions. Photovoltaics (PV) can fulfill this need many times over if deployed over a large enough area. However, if we only apply the current PV technologies for new solar installations, this will require a lot of scarce space. An important question to address is how we can adjust the generation of solar power into the available space, for example through value-added applications such as energy-harvesting windows. On the other hand, nearly 50% of all solar energy is situated in the near-infrared (NIR), which calls for research and development on NIR-PV materials. Organic semiconductors are ideally suited to take up this role as their absorption features can be tuned by clever molecular design. This requires to ‘narrow the optical gap’ of the organic molecules. In this project, we will focus on the tailored design and synthesis of novel NIR-absorbing electron donor polymers and non-fullerene electron acceptors to be combined in the photoactive layer of the envisaged organic solar cells. Whereas past efforts mostly focused on semi-transparent organic photovoltaics, we aim at truly transparent devices without aesthetic or design constraints. The primary focus will be on the fundamental understanding of the structural requirements to achieve full visible transparency and high NIR absorptivity, while simultaneously affording favorable miscibility of the donor and acceptor molecules.