Systematic Synthesis of Lanthanide Phosphate Nanocrystals

Abstract

Uniform LnPO(4).x H(2)O (Ln=Y, La-Nd, Sm-Lu) nanocrystals that have controllable 0D (spherelike), 1D (rodlike), and 2D (polygonlike) structures have been systematically synthesized by means of a hydrothermal method by using a mixed solvent of water and ethanol. Transmission electron microscopy images and SEAD (selected area electron diffraction) patterns revealed that the products are highly crystalline and have structurally uniform shapes. IR, Raman, and electron energy loss spectroscopies gave spectra that indicated that an amount of oleic acid molecules were presented at the surface of individual nanocrystals. These nanocrystals have hydrophobic surfaces and could be easily dispersed in nonpolar solvents. Moreover, a creditable synthetic mechanism for nucleation, growth, and shape evolution has been proposed. Eu(3+) doped products were also prepared by using the same synthetic process. The Eu(3+) doped products exhibited an orange-red luminescence that is ascribed to an electron transition within the 4f shell. Analysis of the photoluminescent spectra revealed that the optical properties are strongly dependent on their morphologies.

Nucleation and Growth of BaFxCl2−x Nanorods

“…[15] Thus, two key factors controlling the properties of nanomaterials are the size and surface characteristics of the nanoparticles. [16][17][18][19] Admittedly, the contention that the size of nanocrystals determines their surface area has been fundamentally accepted; these two factors are interrelated. The nucleation and growth processes of these nanocrystals have been carefully discussed and explained by the Peng group regarding the preparation of semiconductors.…”

“…[20][21][22] Research on how to prepare nanocrystals with controllable sizes and shapes have been reported universally. [12,18,19,[21][22][23][24][25][26][27][28][29][30][31] However, one of the major challenges in the synthesis of nanomaterials is still to gain a comprehensive understanding of monodisperse nanocrystal nucleation and growth, and furthermore, a general and convenient approach to adjust the SSA and control the total surface area of the nanocrystal units, that is, the average surface/atom ratio (d) of inorganic nanomaterials. To meet this challenge, the emphasis of this work is based on a mechanism of surface chemical thermodynamics that can explain the relation between the initial concentration of reactants and the average d value of the final products by a unified and relatively simple synthetic condition alteration.…”

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

“…This procedure yields rounded NPs of NaYF 4 ( Figure 1G) 4 , NaOH and oleic acid in a water/ ethanol solution at temperatures ranging from 100 to 140°C [116]. Likewise, REPO 4 · H 2 O (RE = Y, La-Nd, Sm-Lu) of different morphologies (sphere-like, rod-like and polygon-like, with sizes ranging from 8 to 60 nm, depending on the RE) were synthesized from RE nitrate, NaH 2 PO 4 , oleic acid, and NaOH solutions in water and ethanol treated at 140°C [117]. However, the use of hydrophobic additives finally produces hydrophobic NPs, thus demanding further functionalization treatments.…”

Controlled Synthesis of Bulk Polymer Nanocomposites with Tunable Second Order Nonlinear Optical Properties

“…The crystal structures of LnPO 4 NPs exhibit multiple polymorphic forms with non-centrosymmetric and centrosymmetric symmetry. [ 28 ] Therefore, the centrosymmetric LaPO 4 and non-centrosymmetric hydrated TbPO 4 were selected for the synthesis of homogeneous nanoscale La-Tb phosphate solid solution (La 1−x Tb x PO 4 ). The nanomaterials can be modulated from centrosymmetric to non-centrosymmetric by continuously changing the Tb 3 + content from 0 to 100 mol%.…”