Blue- and white-emitting Dy3+-doped aluminum oxide prepared using precursor synthesis

A(l2)O(3):Dy3+ phosphors have been successfully prepared using the precursor method utilizing Al1-xDyx(OH) (HCOO)(2) as a precursor. The synthesis of the precursor was carried out according to the reaction of the metal nitrates with different concentrations of formic acid. A similar method was used to obtain dysprosium formate, Dy(HCOO)(3), which is the most probable impurity phase formed during the preparation of Al1-xDyx(OH)(HCOO)(2). The crystal structures of Al1-xDyx(OH)(HCOO)(2) and Dy(HCOO)(3) have been studied using X-ray powder diffraction and Raman spectroscopy. The phosphors in the form of their amorphous oxides (Al2O3:Dy3+) and solid solutions ((Al1-xDyx)(2)O-3) with a spinel gamma-Al2O3 structure were obtained via the thermolysis of Al1-xDyx(OH) (HCOO)(2) under a helium atmosphere. The absorption, excitation, and luminescence spectra of the phosphors prepared with different dopant concentrations and upon annealing the Al1-xDyx(OH)(HCOO)(2) precursor at various temperatures were analyzed in detail. For both amorphous Al2O3:Dy3+ and (Al1-xDyx)(2)O-3 phosphors, the luminescence intensity associated with intrinsic internal defects in the aluminum host decreases upon increasing the dysprosium content. The energy transfer from the host to the activator (Dy3+) leads to a shift in the luminescence in the white color region, which is confirmed by the CIE chromaticity coordinates of the (Al1-xDyx)(2)O-3 compounds. The Al22O3:0.005Dy(3+) and gamma-(Al(0.995)Dy0.005)(2)O-3 aluminum oxides exhibit high thermal stability over a wide temperature range and are promising blue-white luminescence materials.

Automated summary

A(l2)O(3):Dy3+ phosphors were successfully prepared using the precursor method. The crystal structures and spectra analysis revealed that increasing dopant concentration led to decreased luminescence intensity and shifted luminescence position. Some of the prepared samples showed high thermal stability and potential for blue-white luminescence.