Sub-5 nm Ln3+-doped BaLuF5 Nanocrystals: A Platform to Realize Upconversion via Interparticle Energy Transfer (IPET)

The upconversion process is reported to occur via interparticle energy transfer (IPET) achieved with Ln(3+)-doped BaLuF5 (Ln = Tm and Yb) nanocrystals in the size range of sub 5 nm. Both Yb3+ and Tm3+ ions are independently doped in BaLuF(5)nanocrystals. Colloidal mixtures containing the above two nanocrystals show strong upconversion emission in the blue, red, and near-IR regions via IPET.