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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.33: Poster

Dienstag, 27. März 2007, 18:00–20:00, Poster B

Raman characterization of vacuum-deposited thin TiOPc films: influence of applied electric field and temperature on polymorphism and orientation — •Britt-Elfriede Schuster, Heiko Peisert, and Thomas Chassé — Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany

Titanyl(IV)phthalocyanine (TiOPc) is an attractive material and a promising candidate for various applications e.g. in optoelectronic devices. As the physical properties of thin organic films are affected by polymorphism and orientation, they are crucial to device efficiency and performance. Therefore, detailed studies of the influences of preparation parameters and effects of ambient conditions are necessary. In the present work we characterize thin TiOPc films prepared by vacuum deposition on various technically relevant model substrates like sapphire, quartz and HOPG. Deposition parameters during the growth (substrate temperature, electric field and film thickness) were systematically varied to study their influences on the growth of these organic films using laterally resolved (confocal) Raman scattering in combination with electronic absorption spectroscopy. In addition, after the growth in UHV, annealing in the temperature range from 298 K to 473 K and applying a DC electric field have been investigated. The Raman spectra are distinctly influenced by details of the growth and postgrowth conditions and they are discussed in terms of a factor group splitting. The results reveal a clear change in the composition of the polymorphic modifications and a variation in molecular arrangement.