Solvent‐Controlled Synthesis and Luminescence Properties of Uniform Eu:YVO₄ Nanophosphors with Different Morphologies

Abstract

A facile solvothermal route has been developed for the preparation of tetragonal europium‐doped yttrium orthovanadate nanoparticles (Eu:YVO4) and is based on a homogeneous precipitation reaction at 120 °C from solutions of rare earth precursors (yttrium acetylacetonate and europium nitrate) and sodium orthovanadate in ethylene glycol or ethylene glycol/water mixtures. The nature of the solvent has a dramatic effect on the morphology and crystallinity of the resulting nanoparticles. Polycrystalline nanoellipsoids (130 × 60 nm) were obtained in pure ethylene glycol, whereas quasispherical nanoparticles (100 nm) with monocrystalline character precipitated in ethylene glycol/water (7:3 by volume) mixtures. To explain these different morphological and structural features, the mechanism of particles formation was investigated. The effects of the doping level on the luminescence properties (emission spectra and luminescence lifetime) were also evaluated to find the optimum nanophosphors. Finally, it is shown that the luminescent efficiency of the quasispherical nanoparticles was higher than that of the nanoellipsoids; this can be related to differences in crystallinity and in impurity content.

Europium-doped NaGd(WO4)2 nanophosphors: synthesis, luminescence and their coating with fluorescein for pH sensing

“…36 The long lifetime values, which are dominant (I01= 60-65%) for all samples (Table 3), can be assigned to the decay time of the Eu 3+ ions located in the nanoparticles bulk, and therefore, not affected by surface effects, 33 As observed in Fig. 6B, the shorter lifetime values, did not show significant variations with the Eu content.…”

“…These include reagents concentrations, temperature, aging time and also the nature of solvents, whose properties (viscosity and dielectric constant) affect the diffusion process involved in the solid phase formation and the possible aggregation behavior of the initially formed particles. 33 In this work, such effects were investigated using EG/H2O mixtures as solvent.…”

Rare earth based nanostructured materials: synthesis, functionalization, properties and bioimaging and biosensing applications

“…Analogously to the aforementioned examples of synthesis at higher temperatures, the slow and controlled release of the RE cations can be achieved by selecting organic precursors of RE and/or by the use of additives, which can form stable complexes with the RE cations. RE acetylacetonates [RE(acac) 3 [86] have been obtained at 120°C from Y(acac) 3 and Na 3 VO 4 after the optimization of the reaction kinetics, which was carried out by adjusting the viscosity and dielectric constant of the solvent (a mixture of EG and water). Similar strategy was applied for the synthesis at 120°C of YPO 4 :Ln 3+ (Ln = Eu, Ce, Tb, and Ce + Tb) NPs with lenticular shape (60 nm diameter) in EG at 120°C [87] and of GdPO 4 :Eu 3+ nanocubes (70 nm edge dimension) in BG ( Figure 1C) [44].…”

“…Fluorides are used for their low phonon energy (<400 cm −1 ), which involves a low probability of NR relaxation and therefore provides improved quantum efficiency [177,178], while phosphates are interesting for their biocompatibility and biodegradability [179]. Other matrices based on vanadates [86,180], oxyfluorides [92], wolframates [181][182][183] and molybdates [184,185] are employed to enhance the global luminescent emission of the DC materials, as it will be detailed later.…”

Water‐Soluble, Monodisperse, Lanthanide‐Doped Y(Gd)VO4 Nanocrystals as Promising Multimodal Bioprobe

“…Those bioprobes combining two or more functions together have high sensitivity and high spatial resolution for diagnosis and the treatment of disease. [35,36] At present, reports on the morphology and optical properties of Y(Gd)VO 4 :Ln 3+ are many, [37][38][39][40][41][42][43] but the applications are relatively few. [32] To sum up, Y(Gd)VO 4 :Ln 3+ nanocrystals can be a good choice for the biomedical domain.…”