Abstract:

0.1-3.0mol% Er ³⁺ -doped TiO₂ powders were prepared by the sol-gel method using the modified titanium (IV) n-butoxide [Ti(O-Bu)_4-x(AcAc)_x] as the precursor which is prepared by chelating reaction between Ti(O-Bu)₄ and acetylacetone (AcAc) at room temperature and 70°C, respectively. The preparation was performed by using iso-propyl (i-PrOH) as solvent with the addition of hydrated erbium nitrated [Er(NO₃)₃·5H₂O]. When the temperature of the chelating reaction increased from room temperature to 70C, both phase transformation temperatures of 1mol% Er3+-doped TiO₂ xerogels from amorphous to anatase and anatase to rutile were decreased about 40C. XRD analysis showed that, sintered at 700C the phase structure for the TiO2 powders prepared by using Ti(O-Bu)_4-x(AcAc)_x chelated at room temperature is anatase, while that for the TiO₂ powders chelated at 70°C is the mixture of anatase and rutile in small amount. The photoluminescence (PL) spectra centered at about 1.53nm with the form of multi-peak were obtained forthe powders by chelating at the two temperature sintered in the temperature range of 400°C. For 1mol% Er ³⁺ -doped TiO₂ powders sintered at 700°C, the PL peak intensity at 1.53μm increased by a factor of 3 with increasing the chelating reaction temperature to 70°C.

Key words: sol-gel method, TiO2, photoluminescence, chelating reaction