Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly.

Monodisperse upconversion GdF3:Yb, Er rhombi by microwave-assisted synthesis

We have synthesized a variety of monodisperse colloidal GdF3:Yb, Er upconversion nanocrystals with different shape, size, and dopants by microwave-assisted synthesis. Typical upconversion emission from Er3+ was observed. In addition to highly monodisperse spherical particles, we were able to prepare monodispersed rhombic-shaped slices that showed a tendency for self-assembly into stacks.

Synthesis of brightly PEGylated luminescent magnetic upconversion nanophosphors for deep tissue and dual MRI imaging.

A method is developed to fabricate monodispersed biocompatible Yb/Er or Yb/Tm doped β-NaGdF4 upconversion phosphors using polyelectrolytes to prevent irreversible particle aggregation during conversion of the precursor, Gd2 O(CO3 )2.H2 O:Yb/Er or Yb/Tm, to β-NaGdF4 :Yb/Er or Yb/Tm. The polyelectrolyte on the outer surface of nanophosphors also provided an amine tag for PEGylation. This method i...

Colloidal dispersion of gold nanorods: Historical background, optical properties, seed-mediated synthesis, shape separation and self-assembly

The color of colloidal dispersions of gold particles in a fluid, typically water, varies from red to blue, depending upon the shape and size of particles. The color and optical properties of gold nanoparticles originate from localized surface plasmons, and are sensitive to their local dielectric environment. Unlike nanospheres, the optical properties, hydrodynamic behavior as well as phase beha...

Single-step synthesis and kinetic mechanism of monodisperse and hexagonal-phase NaYF4:Yb,Er upconversion nanophosphors

A single-step synthesis and the kinetic mechanism for monodisperse and hexagonal-phase NaYF4:Yb, Er upconversion nanophosphors.

A single-step synthesis for monodisperse and hexagonal-phase (beta) NaYF(4):Yb, Er upconversion nanophosphors (UCNPs) with a consistent hexagonal prism shape in the size range from 18 to 200 nm was achieved. The kinetic mechanisms for the particle phase transition and growth were examined. The beta-UCNPs were obtained via co-thermolysis of trifluoroacetate precursors in octadecene (ODE) with co...