Room-Temperature, Ultrafast, and Aqueous-Phase Synthesis of Ultrasmall LaPO4:Ce3+, Tb3+ Nanoparticles with a Photoluminescence Quantum Yield of 74%

LaPO4:Ce3+, Tb3+ nanoparticles with a particle size of 2.7 nm are prepared by a facile room-temperature ligand-assisted coprecipitation method in an aqueous solution. Short-chain butyric acid and butylamine are used as binary ligands and play a critically important role in the synthesis of highly luminescent LaPO4:Ce3+, Tb3+ nanoparticles. The absolute photoluminescence quantum yield as high as 74% can be achieved for extremely small LaPO4:Ce3+, Tb3+ nanoparticles with an optimal composition of La0.4PO4:Ce-0.1 (3+), which is different from La0.4PO4:Ce(0.45)3+ , Tb-0.15(3+) for bulk phosphor. The energy transfer from Ce3+ ions to Tb3+ ions is investigated in sub-3 nm LaPO4:Ce3+, Tb3+ nanoparticles, and Ce3+ ion emission is almost completely suppressed. This room-temperature, ultrafast, and aqueous-phase synthetic strategy is particularly suitable for the large-scale preparation of highly luminescent LaPO4:Ce3+, Tb3+ nanoparticles. LaPO4:Ce3+, Tb3+ nanoparticles (110 g) can be synthesized in one batch, which is perfectly suited to the needs of industrial production.

Automated summary

LaPO4:Ce3+, Tb3+ nanoparticles with a particle size of 2.7 nm were synthesized using a facile room-temperature ligand-assisted coprecipitation method in an aqueous solution. Short-chain butyric acid and butylamine were used as binary ligands and played a critical role in the synthesis of highly luminescent LaPO4:Ce3+, Tb3+ nanoparticles. A high absolute photoluminescence quantum yield of 74% was achieved for La0.4PO4:Ce-0.1(3+) nanoparticles, which is different from La0.4PO4:Ce(0.45)3+, Tb-0.15(3+) for bulk phosphor. Energy transfer from Ce3+ ions to Tb3+ ions was investigated in sub-3 nm LaPO4:Ce3+, Tb3+ nanoparticles, leading to the suppression of Ce3+ ion emission. This room-temperature and aqueous-phase synthetic strategy is suitable for large-scale production of highly luminescent LaPO4:Ce3+, Tb3+ nanoparticles, with up to 110 g synthesized in one batch, catering to industrial needs.