Highly ordered photoluminescent self-assembled films based on polyoxotungstoeuropate complex Na9[EuW10O36]Electronic supplementary information (ESI) available: IR, absorption and emission spectra, XRD pattern and SEM image of EuW10–C16TA film. See www.rsc.org/suppdata/jm/b2/b210965d/

Abstract

A novel highly ordered layered superlattice multibilayer film is prepared by casting the chloroform solutions of ionic complex between a polyoxotungstoeuropate anion EuW10O369− (EuW10) and a hexadecyltrimethylammonium cation (C16TA) on hydrophilic substrates. A variety of techniques, including FT-IR and UV–vis spectroscopies, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to characterize the structure of the composite film. The lamellae consist of alternating layers of polyoxotungstoeuropate and bimolecular layers of surfactant, with the surfactant alkyl chains tilted 30.8° to the lamellar surface and noninterdigititated. The photoluminescent behavior of the film at room temperature has also been investigated by fluorescence spectroscopy to show the characteristic Eu3+ emission pattern of 5D0 → 7Fj. The fluorescence spectra and fluorescence lifetime of the composite film are quite different from those found for EuW10 solid powder and EuW10 dilute aqueous solution.