Investigation of Pr incorporation in LuAG powders and ceramics

An investigation of the luminescence concentration quenching of (Lu_1-xPr_x)₃Al₅O₁₂ (LuAG:Pr) ceramics was carried out coupled with microstructural characterization by means of x-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR) measurements. It was found that the Pr concentration that maximizes luminescence emission depends on the thermal processing conditions. While the calcined LuAG:Pr powder showed maximum luminescence emission for Pr concentrations between 0.18 and 0.33 at.%, maximum emission of ceramic bodies sintered at 1500 °C for 20 hrs. was for Pr concentrations between 0.018 and 0.18 at.%. Further, for short sintering times up to about 3 hrs. luminescence is maximum for Pr concentration around 0.33 at.%. Longer sintering times lead to the formation of PrAlO₃ as a secondary phase, concomitant with a reduction of the intensity of luminescence emission.