Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 77: Focussed Session: Towards a Quantitative Understanding of Complex Adsorption Structures: Surface Science goes Organic III

O 77.3: Talk

Thursday, April 3, 2014, 16:45–17:00, TRE Phy

Site specific mobility boost of caged bisphenol A trimers on Ag(111) — •Özge Sağlam, Julian A. Lloyd, Anthoula C. Papageorgiou, Sybille Fischer, Seung Cheol Oh, Katharina Diller, David A. Duncan, Francesco Allegretti, Florian Klappenberger, Joachim Reichert, and Johannes V. Barth — Physik Department E20, Technische Universität München, Garching, Germany

Artificial molecular rotors, which have been a focus of attention in the last decade of nanoscience, are fascinating subjects not only in terms of fundamental understanding of molecular motion but also due to their promising potential in the context of molecular scale machinery. The construction of regularly oriented two-dimensional arrays of molecular rotors, rather than isolated single rotors, is a key requirement to demonstrate and miniaturize functional systems for signal processing or sensing. Such a molecular system of regular arrays of molecular rotors has been achieved by utilizing a single layer of bisphenol A (BPA) molecules on the weakly corrugated Ag(111) surface. We employ a combined experimental approach using STM, XPS and NEXAFS providing complementary insights regarding self-assembled networks built with BPA molecules on the Ag(111) surface under UHV conditions. Our data reveal temperature-dependent polymorphism, where mobile molecules undergo rotational movements when trapped in the cavities of a nanoporous network. We propose molecular models stabilized by intermolecular hydrogen bonding, and explain the rotational motion of the caged species by their specific adsorption sites.