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2017
ACL
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A.J.Fernández-Carrión, K.Al-Saghir, E.Véron, A.I.Becerro, F.Porcher, W.Wisniewski, G.Matzen, F.Fayon, M.Allix, 'Local Disorder and Tuneable Luminescence in New Sr1-x/2Al2- xSixO4 (x = 0.2, 0.4 and 0.5) Transparent Ceramics', Inorg. Chem. 56 14446-14458 (2017) doi:10.1021/acs.inorgchem.7b01881
Eu-doped Sr1-x/2Al2-xSixO4 (x = 0.2, 0.4 and 0.5) transparent ceramics have been synthesized by full and congruent
crystallization from glasses prepared by aerodynamic levitation and laser-heating method. Structural refinements from synchrotron
and neutron powder diffraction data show that the ceramics adopt a 1x1x2 superstructure compared to the SrAl2O4 hexagonal polymorph.
While the observed superstructure reflections indicate a long-range ordering of the Sr vacancies in the structure, 29Si and
27Al solid-state NMR measurements associated to DFT computations reveal a significant degree of disorder in the fullypolymerized
tetrahedral network. This is evidenced through the presence of Si-O-Si bonds, as well as Si(OAl)4 units at remote
distances of the Sr vacancies and Al(OAl)4 units in the close vicinity of Sr vacancies departing from local charge compensation in
the network. Moreover, luminescence measurements reveal the co-existence of Eu2+ and Eu3+ in the samples, thereby allowing
tuning of the emission color depending on the excitation wavelength. The new single-phase emitting transparent ceramics presented
in this paper appear as promising materials for solid state lighting applications.
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