Effects of Solution Annealing on the Crystallinity and Growth of Conjugated Polymer Nanowires on a Water Substrate

Abstract

Precisely controlling the growth of crystals of self-assembled conjugated polymers (CPs) in organic thin films remains challenging. Here, we designed a new efficient procedure for controlling the growth of self-assembled CP crystals that involved using a solution annealing process to fabricate organic thin films on the surface of water. In the initial stage of this procedure, seed crystals were formed by administering a drop of a solution of CPs onto the surface of the water and then allowing the solvent to evaporate. Then, when we repeated the solution annealing process several times, we obtained a thin film composed of highly crystalline CP nanowires. By varying the number of times the annealing was repeated, we were able to easily and precisely control the growth and crystallinity of the self-assembled CP crystals in thin films floating on the surface of water.