Structural and Optical Characteristics of BaTiO<SUB>3</SUB>:Yb<SUP>3+</SUP> Powders

Abstract

Yb3þ doped Barium Titanate powders were prepared by the sol-gel method in order to study their structural and luminescent properties. These powders have potential to be used to prepare films for luminescent screens. The synthesized powders were obtained at 2, 4 and 8% mol Yb 3þ doped BaTiO 3 . In order to determine organic compound decomposition, weight loss, and establish the crystallization process, we performed TGA and DTA analyses. The powders were also thermally treated at temperatures ranging from 700 to 1200 C in order to study the structure evolution. Pure doped BaTiO 3 powders were carefully studied by X-ray diffraction (XRD). Observations of the powders using scanning electron microscopy (SEM) were done in order to correlate the grain size with the luminescent properties. A comparative study of the spectroscopy properties constituted by emission, absorption spectra, and fluorescence decay measurements using NIR excitation were done. The Yb 3þ ions pairs emission was measured in the green region at about 500 nm when pumping at 940 nm.

Ferroelectric monodisperse Ln-doped barium titanate cuboidal nanocrystals prepared by a solvothermal route

“…Intermediate lanthanide ions, such as Dy 3+ , Ho 3+ and Er 3+ exhibit an amphoteric site-occupation preference for both the A and B sites 29,47,48 whereas the smallest rare earth ions, such as Yb 3+ and Lu 3+ occupy preferentially the B sites 49,50 in the Ln-doped BaTiO 3 nanocubes series, the lanthanoid contraction will lead to sizes of these ions comparable to that of Ti 4+ enabling substitutions could occur at both A- and B-sites. 51–53 A detailed study of the substitutional mechanism in Ln-doped BaTiO 3 nanocrystals, as well as the analysis of the emission spectra are currently underway and will be presented in a forthcoming paper.…”

“…doped BaTiO 3 nanocubes series, the lanthanoid contraction will lead to sizes of these ions comparable to that of Ti 4+ enabling substitutions could occur at both A-and B-sites. [51][52][53] A detailed study of the substitutional mechanism in Lndoped BaTiO 3 nanocrystals, as well as the analysis of the emission spectra are currently underway and will be presented in a forthcoming paper. Various reports published in the literature have suggested that the doping of dielectric perovskites with lanthanoid ions leads to a drastic enhancement of their dielectric properties.…”

“…18,19 Doping with different metals can substantially improve the properties of BaTiO 3 , such as the increase of the dielectric constant value 17 in Ba 1−x La x TiO 3 , and/or the piezoelectric coefficient, as reported for BaTi 1−x Zr x O 3 20 or lead to a positive temperature coefficient of resistivity (PTCR) in rare-earth doped BaTiO 3 -based ceramics 21,22 or multiferroism in BaTi 1−x TM x O 3 (TM = transition metal). [19][20][21][22][23][24][25][26][51][52][53] Conventionally, lanthanide-doped BaTiO 3 powders have been synthesized by solid-state reactions at temperatures above 700 °C. 27 Numerous methods were proposed for the synthesis of lanthanide doped BaTiO 3 nanocrystals; however, most of them involve multiple steps, 28 such as the formation of precursor gels and calcination at high temperatures and/or the presence of a reducing atmosphere yielding products which are contaminated with secondary phases and containing irregularly shaped, and polydisperse nanoparticles.…”