Münster 1999 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

O: Oberflächenphysik

O 47: Fachsitzung

O 47.5: Vortrag

Dienstag, 23. März 1999, 18:45–19:00, PC4

SELF ORDERING OF ORGANIC NOT PLANAR ADSORBATE ON METAL SURFACE - STM, LEED and XPS investigations at ambient and low temperatures — •R. Nowakowski*, C. Seidel, and H. Fuchs — Physikalisches Institut, Universitaet Muenster, Wilhelm Klemm Str. 10

The adsorption behaviour of large, not planar molecules on silver single crystal [110] has been studied by means of variable temperature STM, LEED and XPS. The chosen adsorbate is the derivative of a dye pigment PTCDI: perylene -3,4,9,10 tetra -carboxilic - diimide -di(2,6 isopropylphenyle). Additional two isopropylphenyle rings are rotated versus perylen core which gives molecule their 3-d structure. The adsorbate exhibits high mobility on the surface Ag[110] at room temperature. This is confirmed by the real time STM observations during evaporation. Depending on the degree of coverage in submonolayer range few ordered structures have been distinguished and discussed. Moreover, two different structures of monolayer depending on the preparation procedure have been noted. At low temperatures (100K) the mobility of adsorbate is significantly reduced. The STM studies at various temperatures from 100K to ambient shows the movement of adsorbate in not ordered islands leading to the ordered structures described before. Also a adsorbate induced changes of the substrate is noted. Because the studied adsorbate is not a planar derivative of widely applied dye pigments it is expected that discussed results can be interesting for use in optoelectronic devices since such system should be characterised by the higher electroluminescent efficiency compared to the ones with planar adsorbate.

*Research fellow of the AvHumboldt Foundation, permanent address: Institute of Physical Chemistry, Warsaw, Poland