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Unusual reversibility in molecular break-up of PAHs: the case of pentacene dehydrogenation on Ir(111).

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.

SUBMITTER: Curcio D

PROVIDER: S-EPMC8179676 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Unusual reversibility in molecular break-up of PAHs: the case of pentacene dehydrogenation on Ir(111).

Curcio Davide D Sierda Emil E Pozzo Monica M Bignardi Luca L Sbuelz Luca L Lacovig Paolo P Lizzit Silvano S Alfè Dario D Baraldi Alessandro A

Chemical science 20201103 1

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-induc ...[more]

PMID: 34168740

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