Thermal quenching of Eu2+ emission in Ca- and Sr-Ga2S4 in relation with VRBE schemes
Anna Dobrowolska , B. Dierre , C. M. Fang , H. T. Hintzen , P. Dorenbos
AbstractStructural and optical properties of MGa2S4 (M = Mg, Zn, Ca, Sr, Ba) compounds have been compared, and the vacuum referred binding energy (VRBE) schemes were constructed for the lanthanide ions in the iso-structural compounds CaGa2S4 and SrGa2S4 employing literature data. The VRBE of an electron in the 5d excited state of Eu2+ was found at 0.75 and 0.97 eV below the bottom of the conduction band (CB) in CaGa2S4:Eu and SrGa2S4:Eu, respectively. Such differences explains the unexpected higher thermal quenching temperature reported for Eu2+-doped SrGa2S4 (T50% = ∼475 K) compared to Eu2+-doped CaGa2S4 (T50% = 400 K) The significantly lower VRBE at the CB-bottom in CaGa2S4 versus SrGa2S4 may be explained by the shorter Ga-S bond lengths in SrGa2S4.
|Journal series||Journal of Luminescence, ISSN 0022-2313, (A 35 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||SrGa2S4, CaGa2S4, Thiogallate, VRBE, Thermal quenching|
|ASJC Classification||; ; ; ;|
|Score|| = 35.0, 03-02-2019, ArticleFromJournal|
= 35.0, 03-02-2019, ArticleFromJournal
|Publication indicators||: 2016 = 1.14; : 2017 = 2.732 (2) - 2017=2.577 (5)|
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