Radially oriented anthracene nanowire arrays: preparation, growth mechanism, and optical fluorescence

Radially oriented anthracene nanowires and their self-assembled concentric ring arrays were prepared through a facial solvent-evaporation method. The successful growth of anthracene nanowires can be attributed to a combined mechanism of molecular self-assembly facilitated by strong π-π intermolecular interactions together with evaporation-induced capillary flow and fingering instability. Their radial orientation is determined by the capillary flow; their shape (either straight or curved nanowires) is governed by the competition between the capillary and Marangoni convectional flows. The self-assembly of nanowires into large-scale concentric ring arrays can be interpreted in terms of the repeated slipping-and-sticking motions of the contact line. The high-quality crystalline anthracene nanowire arrays exhibit size-dependent fluorescence emission with high-degree anisotropy.