Structural, luminescence and photophysical properties of novel trimetallic nanocomposite CeO2·ZnO·ZnAl2O4

A novel trimetallic nanocomposite was prepared at a temperature of around 220 °C using co-precipitation of their carbonates from aqueous solutions of the metal nitrates. The morphology of the composite was investigated with scanning electron microscopy (SEM). The X-ray, FTIR and SEM/EDS analyses data indicate that as-synthesized composite which was heated at around 220 °C exists in a nanosized form consisting of crystalline Zn6Al2(OH)16CO3·4H2O and CeO2. Annealing at temperatures between 400 and 920 °C converts the as-synthesized composite to CeO2·ZnO·ZnAl2O4 multi-metal oxide consisting of crystalline CeO2, ZnO and semicrystalline ZnAl2O4. Photoluminescence (PL) spectra of the as-synthesized sample showed emissions at 440 and 590 nm. PL spectra of CeO2·ZnO·ZnAl2O4 annealed at 920 °C was recorded and three sharp lines were observed at 627 nm (1.98 eV), 530 nm (2.34 eV) and 465 nm (2.67 eV) with broad peaks at 540 nm (2.3 eV) and 400 nm (3.1 eV). These sharp lines resemble to those of CeO2 and the broad peaks originate from ZnO. The indirect band gap of the as-synthesized composite was found to be 2.44 eV. The luminescence lifetime at 4 K was measured to be 38 μs.