Fabrication and luminescent properties of (Y0.99Eu0.01)2O3 transparent nanostructured ceramics

Abstract (Y0.99Eu0.01)2O3 nanoceramics have been produced by sintering of stable cubic nanopowders under 8 GPa at temperature in the range of 25–500 °C with the use of Low Temperature High Pressure (LTHP) technique. During consolidation step irreversible phase transition from cubic to monoclinic yttria occurs resulting in two-phase nanoceramics with a grain size in the 10–40 nm range. It has been demonstrated that composite nanoceramics possess a high transmittance in the visible and mid IR ranges due to small light scattering on the nanoscale pores and low birefringence due to extremely small grain size. It has been shown that Eu3+ ions act as a luminescent probe in composite (Y0.99Eu0.01)2O3 nanoceramics since their 4f–4f luminescence strongly depends on the crystallographic environment. The luminescence spectra excited in the charge transfer band (CTB) are presented by superposition of emission from europium ions in cubic and monoclinic yttria. A new wide emission band of (Y0.99Eu0.01)2O3 ceramics in the λ = 500–650 nm wavelengths range (λex. = 307 nm) were attributed to luminescence of Eu3+ ions located in perturbed sites at grain boundaries or interfaces.