Researchers from the Fraunhofer Institute for Solar Energy ISE and the University of Warsaw have demonstrated perovskite photovoltaic cells with significantly improved optoelectronic properties. These cells have a nanoimprinted structured anti-reflective layer with a manufactured honeycomb texture to enhance its performance that could help commercialization of the material in photovoltaic panels on a wider scale.

 

Perovskite-based solar cells are seen as successors to the commonly used silicon cells because of their easy and cost-effective production process, as well as excellent performance, with their panel efficiency and installed capacity photovoltaics being vastly improved. In addition, silicon cells are now approaching their limits of physical efficiency. New solutions are therefore needed that enhance cell efficiency while allowing cheaper and more environmentally friendly production. Perovskite-based cells achieve both criteria, providing efficiency of more than 26%.

 

A problem lies in the integration of perovskite cells with silicon cells while simultaneously reducing losses from reflection and parasitic absorption. To reduce such losses, silicon cells usually have microscopic pyramid patterns etched on their surface by highly corrosive chemical agents, which lessens the reflection of the entire device and increases its current. As perovskites are sensitive to a range of chemical substances, less effective planar anti-reflective coatings tend to be applied.

 

Bringing down optical losses in new types of cells is also a major challenge in terms of their broader implementation. However, as reported in Advanced Materials and Interfaces [Krajewski et al. Adv. Mater. Interfaces (2023) DOI: 10.1002/admi.202300134], here a nanoimprinting method was used to produce an efficient anti-reflective structure with honeycomb-like symmetry that sits on top of the perovskite solar cell.

 

The method allows the production of nanometer-scale structures on very large surfaces, exceeding 100 cm². As researcher Maciej Krajewski said “This approach guarantees scalability in the production process of large-surface devices, which is crucial in the context of the urgent need for energy transformation toward renewable energy sources.”

 

The use of the direct nanoimprinting method makes it possible to produce the complete device in just one technological process, which is key for reducing overall device costs. As well as enhancing efficiency, the application procedure for this layer doesn’t harm the perovskite, which isn’t always the case for anti-reflective structures.

 

As the process is compatible with a tandem configuration for silicon and perovskite cells, there are many possible opportunities for the application. For instance, it has the potential to directly transfer the procedure to emerging photovoltaic architectures, perhaps bringing even more improvements in efficiency.

“This approach guarantees scalability in the production process of large-surface devices, which is crucial in the context of the urgent need for energy transformation toward renewable energy sources.”Maciej Krajewski