Towards well-structured fullerene–phthalocyanine composites: Co-aggregation of fullerene C60 with tetrakis(4-amino-5-phenoxy)phthalocyanine

The paper reports on binary composites prepared from fullerene C60 and π-rich cobalt tetrakis(4-amino-5-phenoxy)phthalocyanine (CoPc) being a mixture of four geometrical isomers. Co-aggregation has been conducted under aqueous and non-aqueous conditions by the Langmuir–Blodgett (LB) technique and drop-casting from o-xylene, respectively. The prepared LB composites are badly disordered whereas the cast ones are predominantly structured: depending on the C60/CoPc ratio, the wire-, worm-, or bead-like particles are observed. Optical spectroscopy is used to reveal the aggregation state of fullerene in the composites. The nano-scale heterogeneities resulting from homomolecular aggregation of fullerene are revealed only in the former case. Smooth co-aggregation under non-aqueous conditions is attributed to intermediate formation of the ternary C60–CoPc–xylene solvates. Formation of the well-shaped composite particles seems to be an optional post-aggregation process being favored by the molecular symmetry of the CoPc isomers.