Attenuated total reflection and emission properties of self-assembled layer-by-layer films containing azobenzene dye

Self-assembled layer-by-layer films were fabricated on Ag-evaporated glass substrates using Direct Red 80 (DR80) azobenzene dye and poly (diallyldimethylammonium chloride) (PDADMAC). The properties of attenuated total reflection (ATR) and emission due to surface plasmon excitation were investigated. The ATR was measured for the Kretschmann configuration of a prism/Ag/layer-by-layer film structure and the emission through the prism was measured when the sample was excited by reverse irradiation in the Kretschmann configuration. The peak angles of the emission spectra almost agreed with the resonant angles of the ATR curves. The shapes of the emission spectra also corresponded to the ATR curves. The structural change of the self-assembled films due to photoisomerization of DR80 molecules was also investigated. From the ATR measurements, the structure of the self-assembled films was found to change due to the photoisomerization by the irradiation of polarized visible light. The surface roughness of the self-assembled films due to the photoisomerization was examined from the scattered light measurements.