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

Abstract

LaPO 4 :Ce 3+ , Tb 3+ 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 LaPO 4 :Ce 3+ , Tb 3+ nanoparticles. The absolute photoluminescence quantum yield as high as 74% can be achieved for extremely small LaPO 4 :Ce 3+ , Tb 3+ nanoparticles with an optimal composition of La 0.4 PO 4 :Ce 0.1 3+ , Tb 0.5 3+ , which is different from La 0.4 PO 4 :Ce 0.45 3+ , Tb 0.15 3+ for bulk phosphor. The energy transfer from Ce 3+ ions to Tb 3+ ions is investigated in sub-3 nm LaPO 4 :Ce 3+ , Tb 3+ nanoparticles, and Ce 3+ 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 LaPO 4 :Ce 3+ , Tb 3+ nanoparticles. LaPO 4 :Ce 3+ , Tb 3+ nanoparticles (110 g) can be synthesized in one batch, which is perfectly suited to the needs of industrial production.

Comment on “Room-Temperature and Ultrafast Synthesis of Highly Luminescent and Extremely Small Eu3+-Doped YVO4 Nanocrystals”

“…This emission performance is extremely close to that of the bulk solid (PLQY = 70% for 5 mol % of Eu 3+ ) . Shortly after, the same group reported in Inorganic Chemistry the synthesis of 2.7 nm LaPO 4 :Ce 3+ ,Tb 3+ nanoparticles with a PLQY of 74%, an extremely high value for nanocrystals of such a small size …”

“…7,15,22 Additionally, the authors state that the ligands ensure complete passivation of surface defects by butyrate/butylammonium ion pairs. 18 If this claim were entirely valid, then all the spectroscopic properties of the obtained nanocrystals should be similar to those of the bulk material, including the optimal Eu 3+ concentration. However, the optimal Eu 3+ concentration (31 mol %) was six times higher than the reported value for the bulk solid (5 mol %).…”

“…14 Shortly after, the same group reported in Inorganic Chemistry the synthesis of 2.7 nm LaPO 4 :Ce 3+ ,Tb 3+ nanoparticles with a PLQY of 74%, an extremely high value for nanocrystals of such a small size. 18 The great appeal justifying the publication of these works stems from the fact that sub-5 nm oxide-based particles easily prepared at room temperature exhibit emission properties nearly identical to those of their bulk counterparts. Nevertheless, based on our experience of over two decades in luminescent rare-earth-doped nanocrystals, particularly YVO 4and LaPO 4 -based compounds, we are convinced this is a misleading fact.…”

Physicochemical Characterization of the Hybrid Molybdate–Tungstate Materials for Solid-State Lighting

“…Suitable hosts for rare earth-based phosphors are known as borates, , alumina, molybdates, − niobates, ,, phosphates, − fluorides, ,− tungstates, − and so on. In the past few years, great attention has been focused on the molybdate–tungstate matrix ,− by virtue of its luminescence and structural properties.…”

Low-temperature in situ preparation of Eu3+/Tb3+-doped CaMoO4/SrMoO4 nanoparticle thin films and their application in anti-counterfeiting

“…36–38 In particular, the nanocrystals with high photoluminescence quantum yields have been successfully synthesized on a large scale at low temperatures. 39–42 This compelling evidence suggests that rare earth-doped molybdates can exhibit favorable luminescent performance even at lower temperatures. The alkaline-earth metal molybdates belong to the tetragonal crystal system with a scheelite structure, exhibiting excellent chemical and thermodynamic stability as well as superior luminescent performance.…”