Influence of Different Ligand Isomers on the Growth of Lanthanide Phosphate Nanoparticles

Abstract

The steric position of the methoxy group in different isomers of methoxycinnamic acid ligands is observed to have a strong impact on the particle growth of lanthanide phosphate nanoparticles. Very small nanoparticles with a mean size of less than 4 nm are obtained for all phosphates from lanthanum to europium, if 3-methoxycinnamic acid or trans-4-methoxycinnamic acid are used as ligands or if these methoxy isomers are replaced by cinnamic acid or phenylpropionic acid. However, if trans-2-methoxycinnamic acid is employed in the synthesis, anisotropic particle growth along the [200] axis is observed, yielding elongated nanoparticles with an average length of up to 25 nm. Our results indicate that in all cases small nanoparticles are formed first at early stages of the synthesis and that these particles grow to larger particles only if trans-2-methoxycinnamic acid is used as the ligand. We assume that the position of the methoxy group in trans-2-methoxycinnamic acid leads to an easier displacement or removal of these ligands from the surface of the small particles, resulting in a less effective shielding of the particles against particle growth.

Energy Transfer between Tb3+ and Eu3+ in LaPO4: Pulsed versus Switched‐off Continuous Wave Excitation

“…The nanocrystals are elongated compared with the size of the LaPO 4 nanocrystals prepared by Haase and co-workers, [31] which is due to the decreasing amount of the complexing agent triethyl phosphate employed. [30] The HRTEM image displays lattice fringes with spacing 0.5 nm for most particles which indicates a highly crystalline material. The measured average size of the nanocrystals is 30 nm compared with that of 34 nm determined from the line broadening in the X-ray diffraction (XRD) pattern ( Figure 2c).…”

“…We take the previous study of Chen and co-workers [29] on similar size nanoparticles of Eu 3+ -doped hexagonal hydrated TbPO 4 as a reference for comparison of our results obtained from nanomaterials prepared by a modified method of Haase and co-workers. [30,31] The relevant energy level schemes of Tb 3+ and Eu 3+ are displayed in Figure 2a.…”

Organic Soluble LaPO4:Eu3+ Nanorods: Sensitization of Surface Eu3+ Ions and Phase Transfer in Water

“…Inorganic compounds such as oxides,, phosphates, fluorides etc. are promising host matrix due to favourable properties like non‐toxicity, thermodynamic stability, high refractive index and chemical stability . These matrices are extensively used for the purpose of lanthanide doping in phosphor material research.…”

“…are promising host matrix due to favourable properties like non-toxicity, thermodynamic stability, high refractive index and chemical stability. [20] These matrices are extensively used for the purpose of lanthanide doping in phosphor material research. The important criterion for the doping of lanthanides in + 3 oxidation state is that the host matrix should accommodate the ions without affecting its stability.…”

A facile hydrothermal route to flower-like single crystalline EuPO4·H2O

“…It is found interestingly that the morphology of EuPO 4 Á H 2 O crystals changed from a sphere-like shape when crystallized in 2 M H 3 PO 4 to elongated hexagonal rods in the presence of additional mineral acids [9][10][11]. EuPO 4 Á H 2 O nanoparticles [12,13], nanowires [14,15], and hollow spheres [16] have been synthesized by different methods. It is still a challenge to prepare lanthanide orthophosphates by a facile, easy controlled manner.…”