Fabrication of TiO₂/CuTiO₃/ sodium alginate nanocomposites of tuned structural, optical, fluorescence and dielectric properties

Abstract This study focuses on the fabrication of nanocomposites consisting of TiO 2 /CuTiO 3 /Sodium alginate, with an emphasis on investigating their structural, optical, fluorescent, and electrical properties. The composite TiO 2 /CuTiO 3 (TO-CTO) was produced by chemical co-precipitation method then different ratios were blended with Sodium alginate (SA). Finally films of the obtained nanocomposite were prepared by casting technique. Characterization of (TO-CTO) powder using XRD diffraction revealed that there are rutile, and anatase TiO 2 phases in the shape of a tetragonal hexagon. Moreover, CuTiO 3 (CTO) structures in the shape of a rhombohedron could be assigned. TiO 2 /CuTiO 3 (TO-CTO) nanocomposites were effectively integrated into sodium alginate (SA) polymers, as confirmed by XRD, ATR-FTIR, and SEM studies. The absorption spectra of the nanocomposites exhibit wide absorption bands that extend from the ultraviolet (UV) region at 260 and 389 nm to the visible spectrum and further into the very near infrared range. The optical band gap values decrease from (3.58 to 2.84 eV) as the weight fraction of TO-CTO increases in the nanocopmosite film. The photoluminescence (PL) emission intensity changes notably when nanofillers are added to the SA and PL spectra of both the rutile and anatase phases of TO appear. Moreover, emission spectra of SA in both the visible (2 to 2.8 eV) and near-infrared (1.4 to 1.54 eV) ranges could be observed, which could be ascribed to the intermolecular hydrogen bonding interactions within the alginate matrix. The rising proportions of TO-CTO oxides in the nanocomposites greatly affect the dielectric properties of the materials and the electrical properties of the TO-CTO/SA system demonstrated considerable variability. The obtained nanocomposites showed interesting UV, PL sensitivity and high dielectric constants can find applications in promising areas, such as photocatalysis, flexible emitting diodes, bio-imaging, and energy storage.