Jump to main content
Jump to site search

Issue 22, 2013
Previous Article Next Article

A XAS study of the luminescent Eu centers in thiosilicate phosphors

Author affiliations

Abstract

Due to its bright yellow-to-red emission, europium doped Ca2SiS4 is a very interesting material for phosphor converted light emitting diodes. The emission spectrum is highly dependent on the Eu concentration and can consist of more than one emission band. We combined X-ray absorption fine structure and photoluminescence measurements to analyze the structure of europium centers in (Ca,Eu)2SiS4 luminescent powders. This paper provides an explanation for the concentration dependency of the emission spectra. We find that at low dopant concentrations a large fraction of trivalent europium ions is unexpectedly present in the powders. These trivalent europium ions tend to form defect clusters in the luminescent powders. Furthermore we observe a preferential substitution of the europium ions over the two different substitutional Ca sites, which changes upon increasing the dopant concentration. At high dopant concentration, the powder crystallizes in the monoclinic Eu2SiS4 structure. Once more a preferential substitution of the europium ions is observed. Summarizing, the influence of the concentration on the emission spectrum is explained by a difference in preferential occupation of the Eu ions in the lattice.

Graphical abstract: A XAS study of the luminescent Eu centers in thiosilicate phosphors

Back to tab navigation

Publication details

The article was received on 03 Dec 2012, accepted on 11 Mar 2013 and first published on 22 Mar 2013


Article type: Paper
DOI: 10.1039/C3CP44334E
Citation: Phys. Chem. Chem. Phys., 2013,15, 8678-8683
  •   Request permissions

    A XAS study of the luminescent Eu centers in thiosilicate phosphors

    K. Korthout, A. B. Parmentier, P. F. Smet and D. Poelman, Phys. Chem. Chem. Phys., 2013, 15, 8678
    DOI: 10.1039/C3CP44334E

Search articles by author

Spotlight

Advertisements