Effect of calcinations temperature on the luminescence intensity and fluorescent lifetime of Tb 3+ -doped hydroxyapatite (Tb-HA) nanocrystallines

Hydroxyapatite luminescent nanocrystallines doped with 6 mol.% Tb 3+ (Tb-HA) were prepared via chemical deposition method and calcined at different temperature, and the effects of calcinations temperature on the luminescence intensity and fluorescent lifetime were studied. TEM image of Tb-HA revealed that the shape of nanocrystallines changed from needle-like to short rod-like and sphere-like with the increase of calcinations temperature; while the particles sizes decreased from 190 nm to 110 nm. The crystallinity degree increased. The typical emission peaks attributed to Tb 3+ ions were observed in emission spectra of 6 mol.% Tb-HA under 378 nm excitation. The luminescent intensity of Tb-HA, which showed the fluorescence quenching, firstly enhanced and then decreased at 700 °C; while the fluorescent lifetime increased firstly and then decreased after 600 °C. Furthermore, the ratio of intensity between 545 nm and 490 nm corresponding to electric-dipole and magnetic-dipole transition ( I R : I O ) increases firstly and then decreases, which revealed that the proportion of substitute type and site of Ca 2+ ions by Tb 3+ ions were helpful to realize the substitute process and functional structure design.