Polymorph-Selektives und Lateral Strukturiertes Wachstum von Dünnfilmen und Einkristallen des organischen Halbleiters Perylen

The polymorphisms of perylene represent an excellent model system for the investigation of fundamental optoelectronic excitations in different crystalline configurations. The prerequisite and the challenge at the same time is the growth of suitable single crystals. Various methods of crystal growth of different phases of perylene are presented here. Both, the growth from solution and the growth by sublimation with regard to a polymorph selectivity are examined in detail. A reliable method for the controlled preparation of well-defined, extended, thin platelets is developed, which is based on a liquid-mediated crystallization in vacuum. A combination of X-ray diffraction and scanning force microscopy allows a complete description of the crystal forms. In addition, scanning force microscopy allows a detailed morphological characterization of perylene single crystals and the identification of structural defects. Highly-ordered single crystals are also characterized by measuring the fluorescence. An elementary tool of this study is confocal laser scanning fluorescence microscopy. In addition to the impressive display of different phases of the perylene, it also allows to measure a spatially resolved spectral information of the fluorescence. Confocal laser scanning fluorescence microscopy is used, in particular, in the investigation of the nucleation of perylene on self-assembled monolayers. In this part of the thesis, a fundamental understanding of the nucleation on various chemically terminated aliphatic thiolates is the goal. A microstructured surface modification is realized by means of microcontact pressure of self-assembled monolayers while perylene is deposited by organic molecular beam deposition.