Porphyrin molecules boost the sensitivity of epitaxial graphene for NH₃ detection

The sensitivity of quasi-free standing epitaxial graphene for NH₃ detection is strongly enhanced by chemical functionalization with cobalt porphyrins resulting in a detection limit well below 100 ppb. Hybridization between NH₃ and cobalt porphyrins induces a charge transfer to graphene and results in a shift of the graphene Fermi-level as detected by Hall measurements and theoretically explained by electronic structure calculations.