DFT and synchrotron radiation study of Eu2+ doped BaAl2O4

Abstract

The structural distortions resulting from the size mismatch between the Eu2+ luminescent centre and the host Ba2+ cation as well as the electronic structure of BaAl2O4:Eu2+(,Dy3+) were studied using density functional theory (DFT) calculations and synchrotron radiation (SR) luminescence spectroscopy. The modified interionic distances as well as differences in the total energies indicate that Eu2+ prefers the smaller of the two possible Ba sites in the BaAl2O4 host. The calculated Eu2+ 4f(7) and 4f(6)5d(1) ground level energies confirm that the excited electrons can reach easily the conduction band for subsequent trapping. In addition to the green luminescence, a weak blue emission band was observed in BaAl2O4:Eu2+,Dy3+ probably due to the creation of a new Ba2+ site due to the effect of water exposure on the host. (C) 2012 Optical Society of AmericaTurku University FoundationJenny and Antti Wihuri Foundation (Finland)Academy of Finland [123976/2006, 134459/2009, 137333/2010, 112816/2006/JH, 116142/2006/JH, 123976/2007/TL]Academy of Sciences of the Czech RepublicCzech research project [AVOZ10100521]European Community [RII3-CT-2004-506008]CNPqNanobiotec-Brasil RH-INAMIinctINAMIFAPESPCoimbra GroupCAPES (Brazil