A study on the local environment of lanthanide ion in nanocrystalline titania

Titania has attracted considerable attentions for its important role in piezoelectricity application. Additionally, lanthanide ion doped titania behaves increased piezoelectricity performance for some systems. It is critical to assess the local environment of lanthanide ions in titania, which will allow greater control over the desired properties. In this work, TiO₂ nanoparticles doped with erbium (III) ion have been prepared by an ultrasonic assistant sol-gel method. The photoacoustic (PA) absorptions of f-f transitions are used to investigate the local environment surrounding erbium (III). The result shows that the environment around erbium (III) is similar to its aqueous ion for the sample heated at 50°C. The degree of covalency for erbium (III) bonding increases continuously during the heat treatment. For the sample calcined at 1100°C, f-f absorptions of erbium (III) show blue shifts. This can be attributed to the formation of erbium titanium oxide phase.