Electronic structure of the SrAl2O4:Eu2+ persistent luminescence material
来源期刊：JOURNAL OF RARE EARTHS2009年第4期
论文作者：Mika Lastusaari Jorma H Janne Niittykoski Pavel Novák Taneli Laamanen
Key words：strontium aluminate; persistent luminescence; electronic structure; DFT calculation; rare earths;
Abstract: The electronic structure of the strontium aluminate (SrAl2O4:Eu2+) materials was studied with a combined experimental and theoretical approach.The UV-VUV synchrotron radiation was applied in the experimental study while the electronic structure of the non-optimized and optimized crystal structure were investigated theoretically by using the density functional theory.The structure of the valence and conduction bands as well as the band gap energy of the material together with the position of the Eu2+ 4f7 87/2 ground state were calculated.The calculated band gap energy (6.4 eV) agreed well with the experimental value of 6.6 eV.The valence band consisted mainly of oxygen states whereas the bottom of the conduction band of strontium states.In agreement with the experimental results,the calculated 4f7 8S7/2 ground state of Eu2+ lies in the energy gap of the host.The position of the 4f7 ground state depended on the Coulomb repulsion strength.The position of the 4f7 ground state with respect to the valence and conduction bands was discussed using theoretical and experimental evidence available.
Mika Lastusaari1，Jorma H2，Janne Niittykoski3，Pavel Novák4，Taneli Laamanen3
(1.o;
2.o)ls(a)(o;
3.Department of Chemistry,University of Turku,FI-20014 Turku,Finland;
4.Institute of Physics,Academy of Sciences of the Czech Republic,CZ-16253 Prague 6,Czech Republic;
5.Graduate School of Materials Research(GSMR)
Abstract:The electronic structure of the strontium aluminate (SrAl2O4:Eu2+) materials was studied with a combined experimental and theoretical approach.The UV-VUV synchrotron radiation was applied in the experimental study while the electronic structure of the non-optimized and optimized crystal structure were investigated theoretically by using the density functional theory.The structure of the valence and conduction bands as well as the band gap energy of the material together with the position of the Eu2+ 4f7 87/2 ground state were calculated.The calculated band gap energy (6.4 eV) agreed well with the experimental value of 6.6 eV.The valence band consisted mainly of oxygen states whereas the bottom of the conduction band of strontium states.In agreement with the experimental results,the calculated 4f7 8S7/2 ground state of Eu2+ lies in the energy gap of the host.The position of the 4f7 ground state depended on the Coulomb repulsion strength.The position of the 4f7 ground state with respect to the valence and conduction bands was discussed using theoretical and experimental evidence available.
Key words:strontium aluminate; persistent luminescence; electronic structure; DFT calculation; rare earths;
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