Laser-Induced Morphology Control and Epitaxy of Dipara-anthracene Produced from the Photochemical Reaction of Anthracene

Abstract

Laser-induced crystal growth and morphology control were observed by irradiation of anthracene in saturated acetonitrile solution. The crystal was composed of dipara-anthracene (DPA), which is a product of intermolecular [4+4] photocycloaddition of anthracene. Polyhedral, skeletal, and dendrite morphologies were controlled by laser fluence. In a suspension system with anthracene microcrystals, laser-induced epitaxy of the photoproduct on the mother anthracene substrate was observed. The a and b axes of the (001) surface of DPA are parallel to the b and a axes of the monoclinic anthracene (001) surface. EpiCalc calculations indicated that almost perfect lattice matching exists between the (1 × 2) supercell dimension at an angle 90°, which is in good agreement with the experimental results. Epitaxy was formed by 2-D nucleation of DPA, which was produced in the solution phase and was brought about by diffusion.