Fluorescence of clay-intercalated xanthene dyes

The fluorescence properties of complexes, which were formed by the intercalation of rhodamine 590 and pyronine Y into a swelling clay, were systematically studied. According to the results of X-ray diffraction analysis, it was observed that the c-axis spacings of the clay could be expanded up to the thickness of the dye molecules with slight lattice distortion of the layers as the quantity of the dye absorbed was increased. For both dye-clay complexes, the emission due to the xanthene chromophore was predominantly observed in the range of 560-590 nm. The maximum quantum peaks shifted gradually towards higher wavelengths and weakened considerably in intensity depending on the swelling of the clay. Such fluorescence profiles were also examined by studying the fluorescence of the dyes absorbed on the surfaces of Al₂O₃.