Synthesis and luminescence properties of Er3+-doped Lu3Ga5O12 nanocrystals

The concentration-dependent luminescence properties of sol-gel-derived nanocrystalline Lu3(1-x)Er3xGa5O12 powders (where x = 0.01, 0.05 and 0.1) have been studied. Laser-excited luminescence spectra, emission decays and upconversion luminescence of Er3+-doped Lu3Ga5O12 nanocrystalline samples have been measured. The decay curve of the (H-2(11/2), S-4(3/2)) emission exhibits a non-exponential behavior presumably due to cross-relaxation process. Moreover, near-infrared to visible upconversion luminescence has been observed in the green region for 1.0 mol% Er3+ ions in Lu3Ga5O12 nanocrystals upon 815 nm excitation. The power dependence of the anti-Stokes luminescence suggests that upconversion is probably achieved through the sequential absorption of two photons. To the best of our knowledge, this is the first report on the preparation and optical properties of Er3+-doped Lu3Ga5O12 in the form of nanocrystalline powders