Influence of the molecular shape on the film growth of a substituted phthalocyanine

Abstract The film growth by physical vapour deposition (PVD) and their subsequent conditioning was studied for Chloro[subphthalocyaninato]boron(III) (C 24 H 12 N 6 BCl, “SubPc”) and its perfluorinated derivative Chloro[dodecafluorosubphthalocyaninato]boron(III) (C 24 F 12 N 6 BCl, “F 12 SubPc”) on a variety of insulating substrates. During preparation in high vacuum the films were characterized in situ by optical absorption spectroscopy (UVvis) and subsequently (ex situ) by atomic force microscopy (AFM) and X-ray diffraction (XRD). Compared to regular phthalocyanines (Pc), these materials showed a decreased intermolecular interaction because of their cone-shaped macrocyclic system. Nevertheless, ordered crystalline growth could be obtained. They therefore represent an example of crystalline molecular layers that already have, however, some characteristics of organic glasses. This may help to overcome the serious problems of grain boundaries dominant in thin Pc films for applications as organic field-effect-transistors (OFET). P-type conduction was indicated for SubPc; n-type conduction is expected for F 12 SubPc. Perfluorination in phthalocyanines leads to clear n-type characteristics. Implementations for the use of these materials in OFET devices are discussed.