Effect of dysprosium ion (Dy3+) doping on morphological, crystal growth and optical properties of TiO2 particles and thin films

Dy3+ doped (0.5, 2.5, 5 and 7.5 wt %) TiO2 particles and thin films were obtained by modified alcoholysis-sol-gel route using tetrabutyl orthotitanate as a precurspor. By controlling the hydrolysis of this precursor through alcoholysis reaction, monodisperse and spherical TiO2 particles were obtained. X-ray diffraction and Raman results confirmed that the Dy3+ doped TiO2 particles are composed of only anatase phase. The Dy3+ doping inhibited any phase transformation and slowed down the particle growth of anatase TiO2. Scanning electron microscopy of bare TiO2 showed monodisperse, spherical and non-aggregated particles. In contrast, the Dy3+doped TiO2 samples exhibited poor dispersity. The luminescence spectra show three characteristic bands at 481, 577 and 683 nm, which are due to 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow), and 4F9/2 → 6H11/2 (red) transitions of trivalent Dy3+ ions. The photoluminescence study revealed the dependence of the luminescent intensity on dopant concentration in TiO2 particles.