Self-Assembled 3D Urchin-Like NaY(MoO₄)₂:Eu³⁺/Tb³⁺ Microarchitectures: Hydrothermal Synthesis and Tunable Emission Colors

Abstract

Novel 3D urchin-like NaY(MoO 4 ) 2 microarchitectures have been successfully synthesized by a complexingagent-assisted hydrothermal process followed by a subsequent heat treatment process. The shape and size of the double alkaline rare earth molybdates precursor microstructures can be tuned effectively by controlling the reaction conditions, such as reaction time, the amount of organic additive trisodium citrate (Cit 3-), and the kinds of organic additives. The possible formation mechanism for urchin-like microarchitectures has been presented. It is found that the Cit 3organic molecule, acting as the chelating agent and shape modifier, plays a key role in fine-tuning the precursor microstructures. The as-formed precursor could transform into NaY(MoO 4 ) 2 with their original urchin-like morphology and slight shrinkage in the size after postannealing process. Under UV and low-voltage electron beam excitation, 5 mol % Eu 3+ and 5 mol % Tb 3+ doped NaY(MoO 4 ) 2 samples exhibit strong red and green emission, corresponding to the characteristic lines of Eu 3+ and Tb 3+ , respectively. Moreover, the luminescence colors of the Eu 3+ and Tb 3+ codoped NaY(MoO 4 ) 2 samples can be tuned from red, yellow, and green-yellow to green by simply adjusting the relative doping concentrations of the activator ions under a single wavelength excitation, which might find potential applications in the fields such as light display systems and optoelectronic devices.

EDTA-mediated morphology and tunable optical properties of Eu3+-doped NaY(MoO4)2 phosphor

“…In the current study, we report an efficient method for the controlled fabrication of novel 3D hierarchical architectures of NaY(MoO 4 ) 2 with a high yield and good uniformity via a facile and mild hydrothermal method in EDTA-mediated processes, which is different from the previous published works [22,[27][28][29]. The effects of the contents of Eu 3?…”

Citric acid-mediated microwave-assisted hydrothermal synthesis and luminescence property of NaSm(MoO4)2 submicro-crystals

“…These impurity peaks don't belong to citric acid or unreacted components (Na 2 MoO 4 and Sm(NO 3 ) 3 ), which indicating the formation of other phases. According to the results of the literatures [13,23], the phases showing such diffraction patterns are still unknown now, so it can be tentatively presumed as the precursor of NaSm(MoO 4 ) 2 microcrystals.…”

“…2b). The citric acid acts as a kind of structure-directing reagent binding to the surface of crystals, which directly affects the growth of different crystal facets by adjusting the growth rate of different facets, resulting in the formation of the nanoparticle structure [23]. When the amount of citric acid was 0.03 g, uniform submicro-particles with the size of about 500 nm have been obtained (Fig.…”

“…-Cit 3-complexes through stronger coordination interaction, decreasing the generation rate of nanoparticles in solution. The relatively slow generation rate of nanoparticles is favorable for the subsequent growth of submicro-particles [23,25]. When enlarged the amount of citric acid to 0.04 g, the nanosheet-like products which were called the precursor of NaSm(MoO 4 ) 2 crystals can be identified (Fig.…”

White light emission materials of self‐assembled rare earth molybdates NaRe(MoO4)2 micro‐particles: the controllable synthesis, growth mechanism and luminescent properties

“…The controlled synthesis of NaY(MoO 4 ) 2 with different shapes and their size/shape-dependent properties were investigated [19][20][21], e.g. Liu et al have tuned the thickness sizes of NaY(MoO 4 ) 2 by adjusting the initial amount of Na 2 MoO 4 and tested photocatalytic activity of as-obtained NaY(MoO 4 ) 2 thin plates for dye degradation under visible light irradiation [22].…”