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EXAFS analysis of blue luminescence in polyoxytungstate citrate gels
Author(s) -
De Buysser Klaartje,
Van Driessche Isabel,
Vermeir Pieter,
Thuy Tran Thi,
Schaubroeck Joseph,
Hoste Serge
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200880255
Subject(s) - octahedron , luminescence , extended x ray absorption fine structure , chemistry , citric acid , ammonium , inorganic chemistry , tetrahedron , crystallography , materials science , absorption spectroscopy , crystal structure , optics , organic chemistry , physics , optoelectronics
Remarkable color changes can be seen when ammonium metatungstate – citric acid gels are submitted to sunlight. The colors strongly depend of the pH values of the precursor solution. Luminescence measurements reveal that gels at pH 7 exhibit a strong blue emission resulting from the presences of WO 4 2– tetrahedra while a slight green emission is due to WO 6 6– octahedra. The shift in equilibrium from octahedral to tetrahedral coordination upon increase in pH is confirmed by detailed EXAFS analysis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)