AVS 47th International Symposium
    Organic Films and Devices Thursday Sessions
       Session OF+EL+SS-ThM

Paper OF+EL+SS-ThM5
Effect of Alkyl Substituents on the Adsorption of Thienylenevinylene Oligomers on the Si(100) Surface

Thursday, October 5, 2000, 9:40 am, Room 313

Session: Organic Thin Films
Presenter: B. Grandidier, IEMN/ISEN, France
Authors: B. Grandidier, IEMN/ISEN, France
J.P. Nys, IEMN/ISEN, France
D. Stievenard, IEMN/ISEN, France
C. Krzeminski, IEMN/ISEN, France
C. Delerue, IEMN/ISEN, France
P. Blanchard, IMMO Universite d'Angers, France
J. Roncali, IMMO Universite d'Angers, France
Correspondent: Click to Email
Conjugated thiophene-based oligomers are subject to intense research activity due among others to their potential use as molecular wires in future molecular electronic devices. As microelectronics technology is based on the use of silicon substrates, there is an increasing need to connect these organic molecules to the existing silicon technology. Due to the low intrinsic solubility of the rigid conjugated chains, the synthesis of the longuest chains required the substitution of alkyl chains to the thiophene ring in order to increase the solubility. Whereas such a substitution has limited effect on the electronic structure of the oligomers, it exerts a strong effect on the interactions of the molecules with their physical and chemical environment. The adsorption of unsubstituted and substituted thienylenevinylene oligomers on the Si(100) surface has been investigated using scanning tunneling microscopy. The mode of substitution of the thiophene ring exerts a strong influence on the adsorption configurations and the images of the oligomer based on 3,4-dihexyl thiophene are highly voltage dependent. We discuss the influence of the alkyl chains on the adsorption process and on the appearance of the molecules in the STM images.