Teams around the world are working flat out to develop perovskite solar cells. In contrast to silicon solar cells, these can also use light in the green and blue parts of the spectrum. Tandem arrangement of perovskite and silicon cells therefore have a potentially higher efficiency. A disadvantage is the typically shorter service life of perovskite solar cells. Research activities usually focus on so-called organometallic hybrid perovskites whose crystal structure consists of inorganic elements such as lead and iodine as well as an organic molecule.
Fully inorganic perovskite semiconductors such as CsPbI3 have the same crystalline architecture as hybrid perovskites, but contain an alkali metal such as cesium instead of an organic molecule. This makes them much more stable than hybrid perovskites, but usually requires a production step at a very high temperature of several hundred degrees Celsius. For this reason, inorganic perovskite semiconductors are difficult to integrate into thin-film solar cells that do not tolerate high temperatures. A team led by Dr. Thomas Unold from the Helmholtz Research Center Berlin has now succeeded in producing inorganic perovskite semiconductors at moderate temperatures so that they could also be used in various thin-film cells in the future.