Researchers at the Technical University of Munich have found that graphene can be combined with porphyrins, the molecules that convey oxygen in haemoglobin and absorb light during photosynthesis, to get a material with exciting new properties. The resulting hybrid structures could be used in the field of molecular electronics, solar cells and in developing new sensors.
The technique involves growing a graphene layer on a surface of silver to use its catalytic properties. Then, under ultra-high vacuum conditions, porphyrin molecules are added. These lose the hydrogen atoms from their periphery when heated on the metal surface, and they end up connecting to the graphene edges.
The researchers used an atomic force microscope to characterize the chemical structure of the molecules. With this tool they observed, for example, a metal being incorporated at the centre of the porphyrins, as well as the specific bond of gas molecules, such as carbon dioxide, without altering the graphene properties.
According to the team, this new graphene ‘functionalization’ technique could be extended to more molecules in the future, which would bond to various carbon nanostructures, like graphene nanoribbons, while also having great potential in the development of electronic applications.