15-20 June 2014
Laurentian University / Université Laurentienne
America/Toronto timezone
Welcome to the 2014 CAP Congress! / Bienvenue au congrès de l'ACP 2014!

Ordered supramolecular polythiophene structures on passivated silicon surfaces.

17 Jun 2014, 09:15
C-304 (Laurentian University / Université Laurentienne)


Laurentian University / Université Laurentienne

Sudbury, Ontario
Oral (Student, Not in Competition) / Orale (Étudiant(e), pas dans la compétition) Surface Science / Science des surfaces (DSS) (T1-8) Surfaces and Thin Films - DCMMP-DSS / Surfaces et couches minces - DPMCM-DSS


Mr Renjie Liu (Lakehead University)


The functionalization of semiconductor surfaces with organic molecules is a necessary step in the development of hybrid organic-semiconductor structures. A significant challenge to organic layer formation is the fact that semiconducting surfaces exhibit a large number of dangling bonds which suppress the diffusivity of adsorbed molecules and can even break the molecules apart via the formation of Si-C bonds. Recently it has been shown that these problems can be obviated by depositing the molecules onto a passivated surface [1]. We have studied the adsorption of brominated tetrathienoanthracene molecules (TBTTA) onto the Si(111)-√3×√3-Ag surface. Thiophene based molecules like TBTTA are of considerable interest in organic semiconductor research due to their efficient conjugation and the chemical stability [2]. The Si(111) √3×√3-Ag surface has no Si dangling bonds and should provide a high mobility surface suitable for TBTTA adsorption. Scanning Tunneling Microscopy images reveal that at low coverage the molecules readily migrate to step edges and defects in the √3 overlayer, in fact many images show direct evidence of molecular mobility. With increasing coverage the molecules eventually form compact supramolecular structures. In terms of the √3 lattice vectors (a and b), the oblique unit cell of the supramolecular structures is am = 3a + b, and bm = a + 2b. These structures are quite fragile and can decompose under repeated STM imaging. Our results suggest that TBTTA is weakly bound to the √3 surface at room temperature and that the supramolecular structures are held together by weak van der Waals forces. 1. T. Suzuki et al., Phys. Chem. Chem. Phys. 11 , 6498–6504 (2009). 2. R. Gutzler et al., Nanoscale 6, 2660-2668 (2014).

Primary author

Mr Renjie Liu (Lakehead University)


Ms Chaoying Fu (McGill University) Prof. Dmytro Perepichka (McGill University) Mark Gallagher (Lakehead University)

Presentation Materials