Comparative study of the luminescent properties of oxide compounds under synchrotron radiation excitation: Lu2O3:Eu nanopowders, ceramics and films

The paper is dedicated to the comparative study of the luminescent properties of Lu2O3:Eu (5%) nanopowders, ceramics and film samples using excitation by the synchrotron radiation in the range of the fundamental absorption edge of Lu2O3 host. The luminescence of F+ centers in the band peaked at 400 nm with a lifetime about of 1.4 ns was observed in Lu2O3:Eu nanopowder. We have also determined the energy of creation of excitons bound with the F+ centers in Lu2O3 host which is equal to 5.36 eV. The notable differences in the luminescence properties of Lu2O3:Eu nanopowder, ceramic and film samples were found which are caused by involvement of the F+ centers at the grain boundaries of ceramics and surface of nanoparticles in the excitation processes of the Eu3+ luminescence in Lu2O3 host. The positions of the high energy levels of the Eu3+ ions in Lu2O3 matrix ware determined in details. We have found also the energy of creation of excitons bound with Eu3+ in the Lu2O3 host which is equal to Eex(Eu) = 5.7 eV at 8 K. Meanwhile, the differences in the Eex(Eu) values in Lu2O3:Eu nanopowders, ceramics and films were also observed to be caused by participation of the host defects and flux impurities in the excitation processes of the Eu3+ luminescence in these samples.