Short-chain ligand synthesis of ytterbium-doped CsPbCl3 perovskite nanocrystals

Synthesis of lanthanide-doped perovskite nanocrystals generally utilizes long-chain ligands like oleylamine and oleic acid at high temperatures up to 260 °C. To tackle this issue, we develop a strategy (temperatures down to 170 °C) to fabricate ytterbium (Yb 3+ )-doped CsPbCl 3 perovskite nanocrystals using the octylamine ligand benefited from its low boiling point and short carbon chain. The as-prepared Yb 3+ -doped CsPbCl 3 perovskite nanocrystals can yield both violet luminescence assigned to exciton recombination and near-infrared emission ascribed to Yb 3+ : 2 F 5/2  →  2 F 7/2 . Structural and spectroscopic characterizations evidence that energy transfer from CsPbCl 3 to Yb 3+ and from defect states to Yb 3+ are simultaneously responsible for the observed Yb 3+ luminescence with quantum yield of 49.5 %. Femtosecond transient absorption spectra confirm that the transferring time scale is within 100 ps, which is much faster than the photoluminescent decay lifetimes of 3000 ps, enabling efficient CsPbCl 3 -to-Yb 3+ energy transfer and thus Yb 3+ luminescence.