Luminescence activity of surface and interior Ge-oxygen deficient centers in silica

Simonpietro Agnello, Maurizio Leone, Viktor Radzig, Magistris, Stefania Grandi

Risultato della ricerca: Articlepeer review

15 Citazioni (Scopus)

Abstract

We report a comparative study on the optical activity of surface and interior Ge–oxygen deficient centers in pressed porous andsol–gel Ge-doped silica, respectively. The experimental approach is based on the temperature dependence of the two photoluminescencebands at 4.2 (singlet–singlet emission,S1!S0) and 3.1 eV (triplet–singlet emission,T1!S0), excited within the absorptionband at about 5 eV. Our data show that the phonon assisted intersystem crossing process, linking the two excited electronic states, more effective for surface than for interior centers in the temperature range 5–300 K. For both centers, a distribution of the activationenergies of the process is found. Based on the results of quantum chemical calculations of the electronic structure of (HO)2Ge:molecule it is suggested that the electronic de-excitation pathway involves two excited triplet states (S1! T2! T1!S0) and showsstructural dependence on the O–Ge–O angle.2005 Elsevier B.V. All rights reserved.
Lingua originaleEnglish
pagine (da-a)1805-1809
Numero di pagine5
RivistaJournal of Non-Crystalline Solids
Volume351
Stato di pubblicazionePublished - 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

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