| AVS 64th International Symposium & Exhibition | |
| Surface Science Division | Monday Sessions |
| Session SS+AS+MI-MoM |
| Session: | Organic/Inorganic Surfaces and Interfaces |
| Presenter: | Piotr Cyganik, Jagiellonian University, Poland |
| Authors: | J. Ossowski, Jagiellonian University, Poland T. Wächter, Universität Heidelberg, Germany T. Żaba, Jagiellonian University, Poland L. Silies, Universität Frankfurt, Germany M. Kind, Universität Frankfurt, Germany A. Noworolska, Jagiellonian University, Poland F. Blobner, Technische Universität München, Germany D. Gnatek, Jagiellonian University, Poland J. Rysz, Jagiellonian University, Poland M. Bolte, Universität Frankfurt, Germany P. Feulner, Technische Universität München, Germany A. Terfort, Universität Frankfurt, Germany M. Zharnikov, Universität Heidelberg, Germany P. Cyganik, Jagiellonian University, Poland |
| Correspondent: | Click to Email |
Selenolate is considered as an alternative to thiolate to serve as a headgroup mediating the formation of self-assembled monolayers (SAMs) on coinage metal substrates. There are however ongoing vivid discussions regarding the advantages and disadvantages of these anchor groups, regarding, in particular, the energetics of the headgroup-substrate interface, thermal stability and their efficiency in terms of charge transport/transfer. Here we introduce a well-defined model system of 6-cyanonaphthalene-2-thiolate and -selenolate SAMs on Au(111) to resolve these controversies. The exact structural arrangements in both types of SAMs are somewhat different, suggesting a better SAM building ability in the case of selenolates [1]. At the same time, both types of SAMs have similar packing densities and molecular orientations [1]. This permitted reliable competitive exchange and ion beam induced desorption experiments which provided an unequivocal evidence for a stronger bonding of selenolates to the substrate as compared to the thiolates [1]. The thermal analysis reveals higher stability of thiolates as compared to selenolates due to the higher stability of the S-C bond as compared to the Se-C which results from stronger bonding of selenolates with the Au(111) substrate [2]. Regardless of these differences, the dynamic charge transfer properties of the thiolate and selenolate based adsorbates were found to be identical as determined by the core-hole-clock approach, which is explained by a redistribution of electron density along the molecular framework, compensating the difference in the substrate-headgroup bond strength [1].
References
[1] Ossowski, J; Wächter, T.; Silies, L.; Kind, M.; Noworolska, A.; Blobner, F.; Gnatek, D.; Rysz, J.; Bolte, M.; Feulner, P.; Terfort*, A.; Cyganik*, P.; Zharnikov*, M., ACS Nano, Thiolate versus Selenolate: Structure, Stability and Charge Transfer Properties, 9, 4508-4526 (2015).
[2] Ossowski J. et al paper in preparation.