Iron in Graphene: Mysterious Transformations Unveiled

Scientists have been buzzing about sticking metal chlorides, especially iron chlorides, into graphite structures. Why? It shields these 2D magnetic systems from the outside world and changes their magnetic, electronic, and optical properties. But hold on, intercalation can cause or reveal defects. These defects can mess with how materials perform. So, let’s talk about what happens when iron chlorides mix with bilayer graphene. Using scanning transmission electron microscopy and some clever calculations, researchers found something interesting. Iron chlorides change phases between FeCl2 and FeCl3 inside graphene. Defects play a big part in these transformations. There are three types: missing iron atoms in FeCl2 areas, extra iron atoms, and iron atoms squeezed in between in FeCl3 areas. Each has its own way of acting. And get this, they discovered a new crystalline phase with an unusual mix of iron and chlorine, Fe5Cl18. No one’s seen this before. These findings help us understand how intercalation works in 2D materials and how tiny defects can affect their properties and tech uses.