How is electricity generated from sunlight? The almost magical transformation that takes place within solar cells is made possible by high-performance, light-absorbing materials: a solar cell is not functional without so-called intermediate layers which surround the active parts of the cell and display special optical and electrical properties. Similar to membranes in biological cells, these layers perform important tasks in solar cells: without them, the energy absorbed at the heart of the solar cell cannot be converted into electrical power.
Researchers at Empa and the EPFL in Lausanne have taken on the important task of optimising the properties of these intermediate layers. By doing so, they are creating the basis for the development of more efficient and more durable solar cells, and for simpler manufacturing processes. In addition to improving available mature technologies, this will also pave the way for novel products, including solar cells that can be exposed to sunlight from both sides and two-stage tandem cells. These too place new requirements on the performance and properties of intermediate layers.