Large-scale electronic structure calculation on blue phosphor BaMgAl 10O17:Eu2+ using tight-binding quantum chemistry method implemented for rare-earth elements

Hiroaki Onuma, Hideyuki Tsuboi, Michihisa Koyama, Akira Endou, Hiromitsu Taraba, Momoji Kubo, Carlos A. Del Carpio, Parasuraman Selvam, Akira Miyamoto

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19 Citations (Scopus)

Abstract

In this study, we carried out large-scale electronic structure calculations on blue phosphor BaMgAl10O17Eu2+ (BAM) using an self-consistent charge (SCC) tight-binding quantum chemistry method with an improved convergence for the 4f orbitais of rare-earth elements. Calculation results obtained by the present method are in good agreement with first-principles and experimental results. We first compared the thermodynamic stability and the electronic structures for three different Eu sites. A first-principles calculation showed that the Beevers-Ross site was the most stable site for the Eu atom. Large-scale electronic structure calculations by the improved SCC tight-binding quantum chemistry method suggested that the electronic structures of Eu 5d orbitais are dependent on the shape of Eu 5d orbitais and the positions of oxygen atoms around the Eu atom. We also investigated the effects of an oxygen vacancy (Vo) on the luminescence properties of BAM. We found that energy levels of molecular orbitais (MOs) with main contributions from Eu 5d orbitais were shifted lower by the Vo near the Eu atom, and thus our results suggested that the formation of the Vo near the Eu atom leads to the red shift of the luminescence color.

Original languageEnglish
Pages (from-to)2534-2541
Number of pages8
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume46
Issue number4 B
DOIs
Publication statusPublished - Apr 24 2007

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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