Structure and optical properties of Dy3+ activated sol-gel ZnO-TiO2 nanocomposites

Dysprosium (Dy3+) activated ZnO-TiO2 nanocomposite phosphors were successfully synthesized by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR), UV–Vis spectroscopy, X-ray photoelectron spectroscopy and photo-luminescent (PL) spectroscopy were used to analyze the structure, morphology, chemical and elemental composition, vibrational bending modes and optical properties of the ZnO-TiO2:Dy3+ nanocomposite phosphors. The XRD patterns confirmed crystallization of wurtzite hexagonal ZnO and tetragonal TiO2 (anatase and rutile) phases. In addition, the XRD patterns showed that secondary phases of ZnTiO3 and Zn2TiO4 were formed. The SEM data showed particle morphology of ZnO-TiO2 nanocomposites consisted of faceted spheres and hexagons which were shown to vary due to incorporation of Dy3+ ions. When excited at 325 nm using monochromatized xenon lamp, the ZnO-TiO2 nanocomposite phosphor exhibited broad emission in the visible region associated with defects in both ZnO and TiO2. The proposed reaction mechanism for ZnO-TiO2 under ultraviolet light irradiation is presented and discussed. The yellowish emission with maximum at ∼587 nm was observed from Dy3+ ions when the nanocomposites were excited at 464 nm using the monochromatized xenon lamp in the blue region of the electromagnetic spectrum. [Display omitted] •Successful synthesis of undoped and Dy3+ ZnO-TiO2 nanocomposites.•Suppression of electron-hole pair recombination within localized states.•Improved catalytic behaviour of the nanocomposites.