In this work, we characterize the adsorption of pentacene molecules on Ir(111) and their behaviour as a function of temperature. While room temperature adsorption preserves the molecular structure of the five benzene rings and the bonds between carbon and hydrogen atoms, we find that complete C-H molecular break up takes place between 450 K and 550 K, eventually resulting in the formation of small graphene islands at temperatures larger than 800 K. Most importantly a reversible temperature-induced dehydrogenation process is found when the system is annealed/cooled in a hydrogen atmosphere with a pressure higher than 5 × 10-7 mbar. This novel process could have interesting implications for the synthesis of larger acenes and for the manipulation of graphene nanoribbon properties.
Unusual reversibility in molecular break-up of PAHs: The case of pentacene dehydrogenation on Ir(111) / Curcio, D.; Sierda, E.; Pozzo, M.; Bignardi, L.; Sbuelz, L.; Lacovig, P.; Lizzit, S.; Alfe, Dario; Baraldi, A.. - In: CHEMICAL SCIENCE. - ISSN 2041-6520. - 12:1(2021), pp. 170-178. [10.1039/d0sc03734f]
Unusual reversibility in molecular break-up of PAHs: The case of pentacene dehydrogenation on Ir(111)
Alfe Dario;
2021
Abstract
In this work, we characterize the adsorption of pentacene molecules on Ir(111) and their behaviour as a function of temperature. While room temperature adsorption preserves the molecular structure of the five benzene rings and the bonds between carbon and hydrogen atoms, we find that complete C-H molecular break up takes place between 450 K and 550 K, eventually resulting in the formation of small graphene islands at temperatures larger than 800 K. Most importantly a reversible temperature-induced dehydrogenation process is found when the system is annealed/cooled in a hydrogen atmosphere with a pressure higher than 5 × 10-7 mbar. This novel process could have interesting implications for the synthesis of larger acenes and for the manipulation of graphene nanoribbon properties.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.