INVESTIGADORES
MORENO Mario Sergio Jesus
artículos
Título:
Improved Route for the Synthesis of Colloidal NaYF4 Nanocrystals and Electron Spin Resonance of Gd3+ Local Probe
Autor/es:
W. IWAMOTO; J.M. VARGAS; L.M. HOLANDA; E. ALVES; M.S. MORENO; S.B. OSEROFF; P.G. PAGLIUSO; C. RETTORI
Revista:
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
Editorial:
AMER SCIENTIFIC PUBLISHERS
Referencias:
Año: 2010 vol. 10 p. 5708 - 5714
ISSN:
1533-4880
Resumen:
This paper presents the synthesis and characterization of colloidal NaYF4
and NaYF4:20% Gd lanthanide nanocrystals. The nanoparticles
were prepared by chemical route using co-thermolysis of Na(CF3COO),
Y(CF3COO)3 and Gd(CF3COO)3
precursor in oleylamine surfactant/phenylether at Ts =
250 °C. By tuning the precursor/surfactant molar ratio during the
process, it was possible to control the crystalline phase, chemical
order and size of the nanocrystals. The nanocrystals were characterized
by Transmission Electron Microscopy, Small Angle X-ray Scattering,
powder X-ray Diffraction, dc-magnetization and Electron Spin
Resonance (ESR) techniques. The ESR experiments show the so called U-spectrum
for the Gd3+ ions in bulk counterpart materials, where
characteristic powder spectra of cubic and lower crystal field
symmetries were observed.