Finely modified crystallites of unsubstituted zinc phthalocyanine for film deposition purposes

Abstract

The present work deals with unsubstituted zinc phthalocyanine (ZnPc), seeking to develop an advanced algorithm for solution-processed ZnPc films. Specifically, it reports on a detailed AFM study of ZnPc crystallites deposited from solution in the binary cyclopentanone–3-dimethylamino-1-propanol system. The crystallization behavior of ZnPc has been radically improved by means of simple aromatic substances added to the dye solution before processing. Varying the nature and quantity of an aromatic additive allows one to change the size, the habit, and even the dimensionality of ZnPc crystallites. Properly modified crystallites are elastic and capable of spontaneous spreading over a solid support. Besides, two alternative kinds of interparticle interactions, namely close agglomeration and seamless fusion, have been explicitly differentiated by AFM phase imaging. The modifying effect of aromatic substances on ZnPc is briefly discussed in terms of supramolecular intercalation of small organic molecules into growing dye crystallites.