Y2O2S and Gd2O2S phosphor lattices activated with a range of Tb3+ concentrations have been successfully prepared as nanoparticles and their emission properties have been characterized using SEM, XRPD, photoluminescence spectroscopy and cathodoluminescence. 5D3–5D4 cross relaxation processes between Tb3+ cations were observed in both Y2O2S and Gd2O2S as a function of Tb3+ concentration.
In the Y2O2S host lattice, the predominant emission colour shifts from blue to green with increased Tb3+ concentration. In contrast, green emission is always predominant in Gd2O2S at Tb3+ concentrations from 0.1 mol% to 5 mol%. This finding is explained in accordance with previous reports on the bulk materials that found the Gd2O2S lattice has a lower charge transfer state than the Y2O2S host lattice.
Yan, X., Fern, G.R., Withnall, R. and Silver, J., 2013. Effects of the host lattice and doping concentration on the colour of Tb 3+ cation emission in Y 2 O 2 S: Tb 3+ and Gd 2 O 2 S: Tb 3+ nanometer sized phosphor particles. Nanoscale, 5(18), pp.8640-8646.
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