Synthesis, characterization, luminescence and defect centres in CaYAl3O7:Eu3+ red phosphor

J Fluoresc. 2011 Jan;21(1):313-20. doi: 10.1007/s10895-010-0718-x. Epub 2010 Oct 1.

Abstract

CaYAl(3)O(7):Eu(3+) phosphor was prepared at furnace temperatures as low as 550°C by a solution combustion method. The formation of crystalline CaYAl(3)O(7):Eu(3+) was confirmed by powder X-Ray diffraction pattern. The prepared phosphor was characterized by SEM, FT-IR and photoluminescence techniques. Photoluminescence measurements indicated that emission spectrum is dominated by the red peak located at 618 nm due to the (5)D(0)-(7)F(2) electric dipole transition of Eu(3+) ions. Electron Spin Resonance (ESR) studies were carried out to identify the centres responsible for the thermoluminescence (TL) peaks. Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0126 is identified as an O(-) ion while centre II with an isotropic g-factor 2.0060 is assigned to an F(+) centre (singly ionized oxygen vacancy). An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F centre (oxygen vacancy with two electrons). The F(+) centre appears to correlate with the observed high temperature TL peak in CaYAl(3)O(7):Eu(3+) phosphor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electron Spin Resonance Spectroscopy
  • Europium / chemistry*
  • Luminescence
  • Microscopy, Electron, Scanning
  • Phosphorus / chemistry*
  • Spectroscopy, Fourier Transform Infrared
  • X-Ray Diffraction

Substances

  • Phosphorus
  • Europium