Investigation of the structural and photoluminescence properties of Ce3+-doped LuAG nanopowders prepared via sol–gel method

• We presented the main results of characterizations obtained on nanophosphors of Ce3+-doped LuAG.
• The sol–gel method is used to prepare the nanopowders, using high purity starting materials and different conditions such as cerium content and annealing temperature.
• The dependence of grain size, strain and luminescence properties with cerium concentration and annealing temperature has been investigated.
• The effects of annealing temperature on the redshift have been discussed.

Ce3+ activated lutetium aluminum garnet nanopowders (LuAG:Ce3+) have been well synthesized using sol–gel method. Both of the effect of Ce3+ concentrations (0.1 at.%, 0.5 at.%, 1.0 at.% and 2.0 at.%) and annealing temperature on the structural and luminescence properties were studied and discussed. The resulting LuAG:Ce3+ nanopowders were characterized by the Differential Scanning Calorimetry (DSC), X-ray diffraction technique (XRD), Fourier transforms infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PL). The DSC analyses have shown that LuAG crystallization temperature is around 960 °C. X-ray diffraction analysis indicated that LuAG crystalline phase was formed as cubic one. By increasing Ce3+ doping concentration we realized that average crystallite size decreases and by increasing the annealing temperature their average size has increased. Moreover, the lattice strain values have diminished during the increase of crystallite size. Room photoluminescence spectra revealed a strong broad green–yellow emission band in the range of 450–700 nm, characteristic to the 5d → 4f (2F5/2, 2F7/2) transitions of Ce3+ ion. It was found that the lowest Ce3+ concentration (0.1 at.%) present the highest luminescence intensity. The effect of crystallite size on the luminescence spectroscopic parameters was investigated.