Preparation, structures and photoluminescent enhancement of CdWO4–TiO2 composite nanofilms

For the first time, Cadmium tungstate (CdWO4)–TiO2 composite nanofilms on a glass substrate were prepared by means of the dip-coating technique, in which collodion was used as a dispersant and film-forming agent. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo gravimetric and thermal analyses (TG/DTA), FTIR and photoluminescence (PL) methods, respectively. SEM and XRD characterization of these films indicated that CdWO4 particles crystallized in a monoclinic wolframite-type structure whereas TiO2 particles were Anatase phase; and both of them were well distributed in the nanofilms. FTIR spectra proved the presence of CdWO4 on the nanofilms. Photoluminescent results showed that the emitting peak of CdWO4 films blue shifted slightly relative to that of CdWO4 crystal. Moreover, the PL intensity of CdWO4–TiO2 composite nanofilm was much higher than that of CdWO4 nanofilm.We ascribed that the introduction of TiO2 should be responsible for the PL enhancement