Cerium doped glasses containing reducing agent for enhanced luminescence

GÖKÇE M., Burgaz G., GÖKÇE A. G.

JOURNAL OF LUMINESCENCE, vol.222, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 222
  • Publication Date: 2020
  • Doi Number: 10.1016/j.jlumin.2020.117175
  • Journal Name: JOURNAL OF LUMINESCENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC
  • Keywords: Cerium, Borogermanate glass, Optical absorption, Luminescence, Reducing agent, XPS, RAY PHOTOELECTRON-SPECTROSCOPY, OPTICAL-PROPERTIES, CE3+ IONS, OXIDE, EMISSION, SPECTRA, CEO2, CONDUCTIVITY, FLUORESCENCE, TRANSITIONS
  • Dokuz Eylül University Affiliated: No

Abstract

Cerium activated oxide glasses have drawn attention because of their potential applications in lasers and high energy scintillators. In this work, CeO2 doped borogermanate (BGG) glasses with high gadolinium content were prepared by melt quenching method in air atmosphere. The optical and luminescence properties were investigated in terms of cerium concentration. The absorption edge is shifted towards longer wavelengths and optical band gap is narrowed due to structural changes in the glass matrix with doping level. Associated structural changes in terms of non-bridging oxygen (NBO) and bridging oxygen (BO) have been investigated by X-ray photoelectron spectroscopy (XPS). Photoluminescence spectra obtained by the direct excitation of Ce3+ ions revealed broad emission band (390 nm) which is attributed to the 5d-4f transition of Ce3+. The optimal doping concentration of cerium ion was determined to be 0.5 mol% whereas further doping levels led to a decrease in Ce3+ emission intensity due to increased Ce4+ concentration. This paper also provides a comparative study using three types of reducing agents including carbon, Sb2O3 and Si3N4 with different concentration levels to evaluate the reduction performance for CeO2 in BGG glasses. Significant improvement in the emission intensity of Ce3+ has been achieved up to a factor of 4.2 via incorporation of reducing agent due to the reduction of Ce4+ to Ce3+. This reduction is further quantitatively supported by Ce 3d XPS spectra. Photoluminescence decay analysis revealed that the decay time of Ce3+ was prolonged with reducing agent confirming the observed improvement of Ce3+ emission in reducing agent doped glasses.