Luminescent hybrid Langmuir-Blodgett films of polyoxometaloeuropate

Luminescent hybrid Langmuir-Blodgett (LB) films of polyoxometaloeuropate (Na₉EuW₁₀O₃₆) were successfully prepared. Low-angle X-ray diffraction data demonstrate that the LB films have a well-defined lamellar structure. The hybrid LB films can exhibit strong luminescence under UV irradiation, which can be observed by the human eye. The effect of the lipid octadecylamine on the luminescence of polyoxometaloeuropate was discussed and compared with that of the lipid dimethyldioctadecylammonium bromide. It is found that the intensity ratio for the ⁵D ₀→⁷F₂ transition to the ⁵D ₀→⁷F₁ transition of europium in two kinds of LB films is quite different. The X-ray photoelectron spectra data verify that there exist different interactions between two lipids and the inorganic polyanions. The different interactions between two lipids and the polyanions may result in the distortion of the site symmetry for europium to a different extent, which may account for the difference in luminescent behavior between the two kinds of LB films.