Thermally driven isotropic crystallinity breaking of nanocrystals: Insight into the assembly of EuS nanoclusters and nanorods with oleate ligands

Abstract

Clusters of EuS nanocrystals formed through the thermal assembly of 2.5 nm nanocrystal monomers by varying the annealing temperature from 300 to 340 °C. Below 310 °C, oleate ligands stabilized on the surface of the EuS nanocrystals, giving rise to their low solubility in triethanolamine while facilitating monomer–monomer oriented attachment into short-chain structures. Above 320 °C, the oleate ligands thermally detached from the surface and were replaced by oleyamine. This reaction mechanism was a multilevel oriented attachment, based on calculations of the nanocrystal growth kinetics, whose evolution gave rise to the formation of EuS nanorods at 340 °C.

Europium chalcogenide magnetic semiconductor nanostructures

“…However, we have also found that it is hard to synthesize small cubes, and difficult to prepare large spheres. While our lab has prepared spheres and cubes, Dickerson has shown some preliminary work demonstrating the ability of EuS to undergo oriented attachment [69] to form nanowires. Hasegawa was able to prepare large quantities of monodispersed cubes (∼12 nm in diameter) that he was able to crystallize into novel superlattices with enhanced coercive fields [70].…”

The evaluation of Coulombic interaction in the oriented-attachment growth of colloidal nanorods

“…In an orientedattachment (OA) growth, interactions between attaching objects govern the kinetics. [4][5][6] To calculate the reaction rate constant and evaluate the kinetic model of an OA growth of one-dimensional (1D) nanorods (NRs), recording the concentrations of attaching objects and the resulting NRs at multiple reaction times is typically required. 6 Recently, the authors reported an analytical expression of the vdW interaction between a nanoparticle and a nanorod, and the calculations of the vdW interaction between the two attaching objects facilitated our understanding on the growth mechanism of the OA growth of the NRs.…”

“…[4][5][6] To calculate the reaction rate constant and evaluate the kinetic model of an OA growth of one-dimensional (1D) nanorods (NRs), recording the concentrations of attaching objects and the resulting NRs at multiple reaction times is typically required. 6 Recently, the authors reported an analytical expression of the vdW interaction between a nanoparticle and a nanorod, and the calculations of the vdW interaction between the two attaching objects facilitated our understanding on the growth mechanism of the OA growth of the NRs. 7 However, due to the lack of an analytical expression of CI between a nanoparticle and a nanorod, the analysis was only centered on the correlation between the OA growth and vdW interaction.…”

A facile synthesis of Te nanoparticles with binary size distribution by green chemistry

“…20 The Te nuclei grew into 27.5 nm NPs possibly through classical Ostwald ripening either by: (a) the bulk phase diffusion of Te from the dissolution of 1.5 nm Te NPs due to their higher dissolvability compared to larger size NPs or (b) the rapid diffusion and recrystallization of multiple Te nuclei shortly after their formation. [21][22][23] The growth showed a rapid kinetics in our synthesis, which reached equilibrium for both NP sizes right after injection of Te precursor into OA solution. Both 1.5 nm and 27.5 nm NPs were liganded by TEA, as confirmed by Fourier transform infrared spectroscopy (FTIR) (see ESI, Fig.…”