Hydrothermal synthesis and photoluminescence of Ce3+ and Tb3+ doped La2Sn2O7 nanocrystals

Phase-pure Ce-/Tb-doped and co-doped lanthanum stannates (La2Sn2O7) nanocrystals were synthesized by a co-precipitation process combined with hydrothermal techniques without any further heat treatment. The crystal structure, particle size, morphologies, and photoluminescence properties of the as-synthesized products were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). The as-prepared samples were single-phase cubic pyrochlore-type nanocrystals with a typical size of 10–20 nm. PL spectra showed a dominating green-emitting line around 544 nm attributing to 5D4–7F5 magnetic dipole transition for Tb3+ doped and Ce3+/Tb3+ co-doped La2Sn2O7 nanocrystals. Meanwhile, the concentration quenching phenomenon was observed in both La2−xTbxSn2O7 and La1.82−xCexTb0.18Sn2O7 nanocrystals. Furthermore, an interesting enhancement of the energy transfer induced green emission was observed in the as-synthesized La1.82−xCexTb0.18Sn2O7 nanocrystals.

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► The pyrochlore structure La1.82−xCexTb0.18Sn2O7 nanocrystals were synthesized.
► La1.82−xCexTb0.18Sn2O7 nanocrystals exhibited green emission.
► An enhancement of the energy transfer induced green emission was observed.