APPLICATION OF A NEAR-FIELD OPTICAL MICROSCOPE TO INVESTIGATE THE FLUORESCENCE ENERGY-TRANSFER BETWEEN CHROMOPHORES EMBEDDED IN LANGMUIR-BLODGETT-FILMS

Scanning near-field optical microscopy (SNOM) was used to investigate the fluorescence energy transfer between a monomolecular film of monom ethin oxacyanine and a layer of monomethin thiacyanine in arachidic ac id, The donor and acceptor chromophores are fixed in Langmuir-Blodgett (LB) films, spaced by the identical chains of the arachidic acid and dye, respectively. The length of these hydrophobic chains guarantees a fixed distance between the different kinds of chromophores. The dye m olecules are oriented parallel to the plane of the LB film, In the LB layer assembly, a step was prepared to separate two different regions. One area contains both kinds of chromphores, whereas in the other are a only the donor dyes are present, We used the SNOM technique because of the possibility to measure simultaneously the fluorescence behaviou r and topographical structure. (C) 1997 by John Wiley & Sons, Ltd.