Synthesis Improvement of Yb³⁺-Activated SnO₂ Nanocrystals

Yb3+ doped SnO2 nanocrystals were synthesized, using the hydrolytic route in the presence of starch as the size stabilizer. Starting from salt precursors, the nanopowders obtained with various Yb3+ loads are thermally stable up to 600 °C. They were characterized by XRD, solid state NMR, TEM, ICP and TG-MS techniques. The nanocrystal Cassiterite structure, with a size of a few nanometers (<6 nm), was identified by XRD, NMR and Raman measurements confirming a homogeneous dispersion of Yb3+ ions in the lattice. The preliminary assessment of the spectroscopic features of nanocrystals was performed by absorption and photoluminescence spectroscopy. The typical Yb3+ absorption peak, centred at 977 nm, and an intense 2F5/2→ 2F7/2 Yb3+ emission band were observed.