Paper NS-MoA3
Enhanced Photoluminescence from Gd₂O₃:Eu³⁺ Based Core/Multi-shell Nanoparticles

Monday, October 31, 2011, 2:40 pm, Room 203

Core/shell and core/multi-shell nanoparticles with luminescent Gd₂O₃:Eu³⁺ were successfully synthesized by a high boiling-point alcohol (polyol) and solution precipitation methods, respectively. The hetero-structured nanoparticles with Eu doped Gd₂O₃ exhibited intense ⁵D₀-⁷F₂ photoluminescence (PL) from Eu³⁺ after calcination at 600 ˚C for 2h in air. Photoluminescence excitation (PLE) data showed that while a small fraction of the emission resulted from direct excitation of Eu³⁺, most of the excitation resulted from adsorption in the Oxygen to Europium charge-transfer band (CTB) between 225 and 275 nm. Gd₂O₃:Eu³⁺/Y₂O₃ core/shell nanoparticles exhibited PL intensities up to 40% larger than from bare Gd₂O₃:Eu³⁺ nanoparticles and SiO₂/Gd₂O₃:Eu³⁺/Y₂O₃ core/multi-shell samples showed quantum yield (QY) up to 72% larger than that of SiO₂/Gd₂O₃:Eu³⁺ core/single-shell nanoparticles. The increased PL and QY were attributed to reduced non-radiative recombination based on longer luminescence decay time. Potential applications of the nanoparticles as scintillation radiation detectors will be discussed.