Speakers: Tobias Meier, Rémy Pawlak (Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland)
Place: Cukrovarnická 10, budova A, knihovna, 1. patro
Presented in English
Organisers:
Department of Thin Films and Nanostructures
Electron donor-acceptor molecules are promising candidates for molecular electronic devices since they may generate separated electron-hole pairs upon absorption of photons. To preserve the intrinsic electronic character of such complexes upon adsorption, a particular attention must be focused on their interaction with the underlying surface. In this contribution, we will first show the adsorption of TTF-dppz [1], a fused piconjugated donor-acceptor molecule, deposited on insulating NaCl films on Cu(111). To investigate the interplay between the atomic structures of TTF-dppz and NaCl, we performed high-resolution scanning tunneling (STM) and atomic force microscopy (AFM) measurements at 5 K with CO-terminated tips. The charge distribution above individual molecules has been studied by local contact potential mapping [2,3] which reveals the coexistence of two charge redistribution depending on the adsorption site. In agreement with numerical calculations [4], such variation of the TTF-dppz properties is found to arise from the formation or not of a complex with a single Na+ ion of the surface. In a second example, we will describe the adsorption of porphyrin derivatives on hydroxylated rutile-TiO2(110). The interaction of the single molecules with the hydroxyl groups (OH) of the rutile surface has been particularly regarded by a combined STM/AFM study. We found that a relevant change of the charge distribution of those molecules is provoked by the presence or not of OH groups underneath [5]. Finally, we will discuss our first results on the adsorption ofphtalocyanin molecules on a topological insulator (Bi2Te3).
[1] C. Jia et al., Chem. Eur. J. 13, 3804 (2007).
[2] S. Kawai et al., ACS Nano 7, 9098 (2013).
[3] B. Schuler et al., Nano Lett. 14, 3342 (2014).
[4] P. Hapala et al., Phys. Rev. B 90, 085421 (2014).
[5] R. Pawlak et al. To be submitted.
Copyright © 2008-2014, Fyzikální ústav AV ČR, v. v. i.
