Structural and Optical Properties of Mixed Diindenoperylene-Perfluoropentacene Thin Films

摘要

Mixed films of perfluorinated pentacene and diindenoperylene are studied for their structural and optical properties on SiO2 and glass substrates. Grazing incidence X-ray diffraction shows that the compounds mix on the molecular level. Two structures are identified. Their out-of-plane lattice spacing is determined by X-ray reflectivity, and their growth morphology is characterized using atomic force microscopy. It is found that one structure consists of molecules in a standing-up and the other in a lying-down orientation. The uniaxial dielectric function of mixed films is determinedwith spectroscopic ellipsometry, and the in-plane optical extinction coefficient is measured by real-time differential reflectance spectroscopy during growth. The question of intermolecular coupling between perfluorinated pentacene and diindenoperylene is discussed.