Abstract: The squaraine dye 2-[4-(dibenzylamino)phenyl]-4-[4-(dibenzylimino)-2.5-cyclohexadienylidene]-3-oxo-1-cyclobuten-1-olate(NK2846)can be incorporated into composite monolayers with arachidic acid(C₂₀)at the air-water interface.The composite monolayers including the dye can be transferred onto a glass slide with hydrophobic surface by vertical dipping method as typical Y films.The aggregation of the squaraine dye in the LB films was studied by absorption spectroscopy.It was found that the absorption curve of LB films with squaraine dye covers most of the visible region and extends to the near IR,because of the aggregation of dye molecules(or intermolecular interaction)in LB films.Polarized UV-visible spectroscopy indicated that there is partial anisotropy of dye molecules presentedin the layer plane.

Key words: squaraine dye, aggregate, LB film, anisotropy