Template synthesis of cyanine dye H-aggregates on nanostructured [6,6]-phenyl C61-butyric acid methyl ester substrates

Abstract

A novel and general method for the synthesis of H-aggregates is presented. H-aggregates can be precipitated from solutions of cyanine dyes in nanostructured [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM) template films. H-aggregates synthesized that way have a narrow line shape width comparable to the smallest H-bands reported for thin films so far. We demonstrate that H-aggregates can be induced in different cyanine dyes (trimethine-, pentamethine- and heptamethine dyes). Aggregation follows a universal pathway, the concentration dependence of aggregation for different dyes can be scaled to fall onto one master curve. According to our model, H-aggregates have the form of 3D-crystals that form within cavities of the template. The template substrate is fabricated by means of a phase separation process of PCBM with a specific cyanine dye and consecutive selective dissolution of the dye. The dimensions of the template cavities have a major influence on aggregation.