Researchers at Eindhoven University of Technology (TU/e) and research institute ECN (part of the Solliance collective) have found that adding a thin layer of aluminum oxide helps protect a perovskite solar cell against humidity, as well as add a yield boost of 3%.
The scientists covered the sensitive layer of perovskite with a few atomic layers of aluminum oxide to protect against degradation caused by humidity. These layers are contained within the solar cell, between the layers of perovskite and electric contact. The researchers chose aluminum oxide (Al2O3) since it can form immediately on any kind of surface. The team explained that despite the fact that Al2O3 has electrically insulating properties, it can still be used as a buffer layer between the semi-conductive perovskite and the conductive contacts by limiting the thickness of the layer to one nanometer or less. This way, charge carriers can then tunnel electrically through the insulator layer.