Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 3: Organic Thin Films
DS 3.3: Vortrag
Montag, 25. Februar 2008, 15:00–15:15, H 2013
Mixing and phase-separation in co-deposited films of rod-like conjugated molecules — •Jörn-Oliver Vogel1, Ricarda Opitz1, Ingo Salzmann1, Steffen Duhm1, Bert Nickel2, Jürgen Rabe1, and Norbert Koch1 — 1Humboldt-Universität zu Berlin, Berlin, Deutschland — 2Ludwig-Maximilians-Universität, München, Deutschland
Pairs of rod-like conjugated molecular materials [sexithiophene (6T), p-sexiphenyl (6P), dihexylsexithiophene (DH6T), quaterthiophene (4T), and pentacene] were co-deposited by organic molecular beam deposition on silicon oxide. We studied the properties of thin film samples by atomic force microscopy (AFM), X-ray diffraction (XRD), and infrared spectroscopy (IR). The co-deposition of pairs of molecules with similarly sized conjugated cores (e.g., 6T/6P) resulted in layered structures with mutual intercalation of the molecules. In contrast, co-deposition of molecules with differently sized conjugated cores led to two different morphologies: (i) Pairs of non-alkylated molecules (e.g., 4T/6P) formed fibrous amorphous films. (ii) Pairs of alkylated and non-alkylated molecules (e.g., DH6T/4T) exhibited phase separation with crystalline structures comparable to the ones of the pure materials. Our results suggest that a similar size of the conjugated cores of two co-deposited molecular materials is a key prerequisite for the formation of layered structures with mutual intercalation of the molecules. The particular type of the conjugated molecular moiety seems not to play an important role.