Spectral properties and structure of the J-aggregates of pseudoisocyanine dye in layered silicate films.

Hybrid films composed of pseudoisocyanine (PIC) and layered silicates were prepared by direct adsorption from dye solution. Properties of the films were characterized by absorption and fluorescence spectroscopy, which indicated the formation of two types of J-molecular aggregates. Molecular arrangement and structure of the J-aggregates were investigated by means of linearly polarized absorption spectroscopy and X-ray diffraction (XRD). Structural models of the two main types of J-aggregates with oblique and those of parallel molecular alignments were designed. The spectral properties of these species were studied in detail. All the films contained a mixture of both types of the J-molecular assemblies. Predominance of either species likely depends on the layer charge of the silicate template.