Heteroepitaxy of Perfluoropentacene (C 22 F 14 ) on the Single Crystal Surface of Pentacene (C 22 H 14 )

Heterojunctions of π -conjugated molecules are fundamentals of electronic functionalities in organic semiconductor devices, yet the leading principles determining the structures of the molecular heterojunctions are still unestablished. In the present study, a well-defined organic “ complementary ” pn-heterojunction of perfluoropentacene (C 22 F 14 ) overlayers formed on the single crystal surface of pentacene (C 22 H 14 ) was examined by means of grazing-incidence x-ray diffraction and atomic force microscopy. It is revealed that the perfluoropentacene molecules crystallize epitaxially to align their nearest-neighbor direction ({010} axis) along the {1¯10} axis of the pentacene single crystal.