Structural and spectroscopic study of Ho³⁺ -doped nanotitania host prepared using a sol-gel technique

Holmium (Ho³⁺ )-doped TiO₂ solid laser active materials with different concentrations (1, 3, 5, and 7 wt%) of Ho³⁺ ions were prepared using a sol-gel method. A structural study of the samples using X-ray diffraction (XRD) revealed the anatase phase of pure and doped TiO₂ calcined at 500°C, which is confirmed by (101), (004), (200), (105), (211), (204), (116), (220) and (215) diffraction peaks. XRD analysis showen a deformation along the c-axis of the anatase lattice constant with doping, and a random change in the grain size of the doped titania with respect to pure samples. The presence of the titania bonds (Ti-O-Ti) and (Ti-O) of pure and Ho³⁺ -doped samples were confirmed from the FTIR spectroscopy study of the samples. In addition, it was noted that bands around 1338, and 1339 cm^-1 belonging to 3, 5, and 7 wt% dopant concentrations, while no band for 1 wt% was observed. UV-Vis spectrophotometer and spectrofluorophotometer techniques were used to study the optical and spectroscopic characterizations of these samples. It was found that various fluorescence peaks for Ho³⁺ ions were observed in the UV-vis region under different pump wavelengths. This is a good indication of suitability of the material to be employed as a laser active medium.