Direct Formation and Luminescence of Nanocrystals in the System Eu2Sn2O7–Gd2Sn2O7 Complete Solid Solutions |
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Authors: | Masanori Hirano Toshiaki Ohmori |
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Affiliation: | Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, Toyota, Japan |
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Abstract: | Nanocrystals with orange‐reddish luminescence based on the pyrochlore‐type complete solid solutions with cube‐like morphology in the Eu2Sn2O7–Gd2Sn2O7 system were directly formed from the precursor solutions of SnCl4, GdCl3, and EuCl3 under weakly basic hydrothermal conditions at temperatures higher than 180°C for 5 h. The crystallite of Gd2Sn2O7 pyrochlore gradually grew from 10 to 37 nm as the hydrothermal treatment temperature rose from 180°C to 240°C. The lattice parameter of cubic phase linearly increased with increased europium concentration according to the Vegard's law. The characteristic orange‐reddish photoluminescence spectra of Gd2Sn2O7:Eu3+ cubelike nanocrystals with crystallite size from 34 to 37 nm that were formed at 240°C for 5 h were attributed to the most sharp orange (586 nm) luminescence with high intensity and quite broad red (610–630 nm) emission with weak intensity, according to the 5D0→7F1 and 5D0→7F2 transitions of Eu3+, respectively. At a composition of (Eu0.09Gd0.91)2Sn2O7, the intensity of orange emission reached the maximum. The Red‐to‐Orange (5D0→7F2/5D0→7F1) (R/O) emission intensity ratio was in the low range from 0.10 to 0.14, which was a characteristic of Gd2Sn2O7:Eu3+. |
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