The control of molecular self-association in spin-coated films of substituted phthalocyanines

Uniform thin films are needed for the exploration and exploitation of the fascinating optical and electronic properties of the phthalocyanine (Pc) macrocycle. Spin-coating has been demonstrated to be a simple, fast and reproducible method of fabricating uniform films. However, solubility in a volatile organic solvent is a prerequisite for this technique and previous studies have shown that groups placed on the Pc macrocycle can have a profound effect on the nanoscale structure of the resulting film. In this paper we attempt to establish some fundamental structure-property relationships which determine the molecular packing within such films. Previous studies are reviewed and the film forming properties of a number of Pc derivatives are examined. In particular, the formation of films in which the Pc cores are isolated from each other by the use of novel, sterically crowded hexadeca-substituted Pcs is examined.