Details

Autor(en) / Beteiligte

• Xie, Hongde
• Lu, Juan
• Guan, Ying
• Huang, Yanlin
• Wei, Donglei
• Seo, Hyo Jin

Titel

Abnormal Reduction, Eu3+ → Eu2+, and Defect Centers in Eu3+-Doped Pollucite, CsAlSi2O6, Prepared in an Oxidizing Atmosphere

Ist Teil von

• Inorganic chemistry, 2014-01, Vol.53 (2), p.827-834

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Eu-doped pollucite CsAlSi2O6 was synthesized by the sol–gel method and heated in an air atmosphere. The crystal structure and the microstructure of the phosphors were investigated by X-ray powder diffraction and SEM images, respectively. The photoluminescence spectra and temperature dependent decay curves were measured. An abnormal reduction phenomenon of Eu3+ → Eu2+ was reported when Eu3+ ions were doped in alkaline metal cation sites in CsAlSi2O6 prepared in an oxidizing atmosphere. The abnormal mechanism was discussed on the basis of the charge compensation model and a rigid three-dimensional framework structure of CsAlSi2O6. The luminescence color centers were investigated by luminescence decay lifetimes and thermal stabilities of Eu2+ ions. The defect complexes of [(Eu3+ Cs)••–2VCs′] or [(Eu3+ Cs)••–Oi″] induced by the substitution of Eu3+ on Cs+ were suggested in the lattices. Eu2+ ions could be regarded as Eu3+ ions combining with the released electrons from defects Oi″ or VCs′ in close vicinity of Eu3+ (Eu3+ + e); the electrons cannot enter the atom track of Eu2+ presenting luminescence of Eu2+ ions. The results indicate that several defect traps can be attributed to the abnormal reduction mechanism of Eu3+ to Eu2+ ions in a matrix.