The effect of Nd³⁺ concentration on fabrication, microstructure, and luminescent properties of anisotropic S‐FAP ceramics

Abstract

Nd 3+ doped strontium fluorophosphate (S-FAP), with chemical formula Sr 5 (PO 4 ) 3 F, nanopowders were prepared using the co-precipitation method. The prepared powders had no impurity phase with a grain size of about 30 nm and the doping limit of Nd 3+ ions in strontium fluorophosphate is about 9 at.%. The morphology and particle size were determined by the doping concentration of Nd 3+ . Anisotropic Nd: S-FAP transparent ceramics with different Nd 3+ doping concentrations were fabricated successfully by the simple hot-pressing method. The grain size of prepared S-FAP transparent ceramics decreased first and then increased with the increase of Nd 3+ concentration. The 2 at.% Nd: S-FAP ceramic presented the highest optical transmittance at all wavelengths range. The characteristic transitions from the ground state to the excited states of Nd 3+ ions were observed from the absorption spectra, and the absorption cross-section was calculated at 3.71 × 10 -20 cm 2 . The influence of Nd 3+ ion concentration on luminescence intensity and fluorescence lifetime was studied under 796 nm excitation. The strong emission of 4 F 3/2 → 4 I 9/2 transition in Nd: S-FAP was calculated by Judd-Ofelt (J-O) theory.