Aggregate formation of Rhodamine 6G in anisotropic solvents.

The aggregation of Rhodamine 6G in liquid crystalline solutions was studied using polarised spectroscopy and in a guest-host system based on homogeneous-homeotropic alignment. The orientation of the dye molecules (guest) was controlled using an electric field, and this enabled the contrast ratio R of the dye to be obtained by electrically switching. The excitonic treatment of the absorption spectra suggests a coplanar structure for the dimeric aggregates.