On the correlation between the composition of Pr3+ doped garnet type materials and their photoluminescence properties

Lu3(Al,Ga)5O12 and (Y,Lu)3(Al,Mg,Si)5O12 samples doped with 1% Pr3+ were prepared by two aqueous sol–gel chemistry approaches, such as citrate and glycolate methods. All samples were characterised by powder X-ray diffraction (XRD), thermal quenching (TQ), fluorescence lifetime measurements and photoluminescence (PL) techniques. It turned out that the Pr3+ emission is very sensitive to the composition of the garnet host lattice. Lu3Al5O12:Pr3+ samples showed mainly [Xe]4f15d1→[Xe]4f2 broad band emission in UV–blue region, whereas [Xe]4f2–[Xe]4f2 line emission of Pr3+ dominated in Lu3Ga5O12 samples. Modification of garnet crystals with Mg2+–Si4+ pair has led to generation of strong crystal field strength resulting in energy transfer from 5d to 4f orbitals. Y3AlMg2Si2O12 composition generated the strongest crystal field splitting out of all synthesised samples and showed practically only Pr3+ [Xe]4f2–[Xe]4f2 line emission in the red spectral region.