Considerable Improvement of Long-Persistent Luminescence in Germanium and Tin Substituted ZnGa2O4

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• 作者：Mathieu Allix ; S茅bastien Chenu ; Emmanuel V茅ron ; Thomas Poumeyrol ; El Amin Kouadri-Boudjelthia ; Salaheddine Alahrach茅 ; Florence Porcher ; Dominique Massiot ; Franck Fayon
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：May 14, 2013
• 年：2013
• 卷：25
• 期：9
• 页码：1600-1606
• 全文大小：382K
• 年卷期：v.25,no.9(May 14, 2013)
• ISSN：1520-5002

文摘

The red long-lasting luminescence properties of the ZnGa₂O₄:Cr³⁺ spinel material are shown to be much improved when germanium or tin is substituted to the nominal composition. The resulting Zn_1+xGa_2鈥?x(Ge/Sn)_xO₄ (0 鈮?x 鈮?0.5) spinel solid solutions synthesized here by a classic solid state method have been structurally characterized by X-ray and neutron powder diffraction refinements coupled to ⁷¹Ga solid state NMR studies. In contrast to ZnGa₂O₄:Cr³⁺ for which long lasting luminescence properties have been reported to arise from tetrahedral positively charged defects resulting from the spinel inversion, our results show that a different mechanism occurs complementary for Zn_1+xGa_2鈥?x(Ge/Sn)_xO₄. Here, the great enhancement of the brightness and decay time of the long lasting luminescence properties is directly driven by the substitution mechanism which creates distorted octahedral sites surrounded by octahedral Ge and Sn positive substitutional defects which likely act as new efficient traps.

Keywords:

red long-lasting phosphorescence; Ge or Sn substituted zinc gallate spinel oxides; neutron powder diffraction; ⁷¹Ga solid state NMR