Improved persistent luminescence of CaTiO3:Pr by fluorine substitution and thermochemical treatment

JOURNAL OF ALLOYS AND COMPOUNDS

卷:613

Article

Yoon, Songhak¹  Otal, Eugenio H.¹  Maegli, Alexandra E.¹  Karvonen, Lassi¹  Matam, Santhosh K.¹  Ebbinghaus, Stefan G.²  Walfort, Bernhard³  Hagemann, Hans⁴  Pokrant, Simone¹  Weidenkaff, Anke^1,5 

[1] Empa Swiss Fed Labs Mat Sci & Technol, Lab Solid State Chem & Catalysis, CH-8600 Dubendorf, Switzerland

[2] Univ Halle Wittenberg, Inst Chem, D-06120 Halle, Germany

[3] LumiNova AG, CH-9053 Teufen, Switzerland

[4] Univ Geneva, Dept Phys Chem, CH-1211 Geneva 4, Switzerland

[5] Univ Stuttgart, Inst Mat Sci, D-70569 Stuttgart, Germany

关键词: CaTiO3:Pr;    Fluorination;    Persistent luminescence;    Afterglow;    X-ray diffraction;   

DOI  :  10.1016/j.jallcom.2014.06.041

来源: Elsevier

【 摘 要 】

Fluorine-substituted CaTiO3:Pr phosphors were prepared by a solid-state reaction. Rietveld refinements of powder X-ray diffraction patterns revealed that increasing fluorine-substitution leads to the gradual shrinkage of the unit-cell. Enhanced afterglow intensities were observed with fluorine-substitution. Furthermore, the effect of annealing atmosphere was investigated by thermochemical treatment in different atmospheres (Ar, air and NH3). UV-Vis diffuse reflectance spectra and photoluminescence excitation spectra revealed that Pr4+ in the pristine CaTi(O,F)(3):Pr phosphor was partially reduced to Pr3+ under NH3 flow leading to an intensity improvement of ca. 450% compared to CaTiO3:Pr. The substantial improvement of afterglow intensity by fluorine substitution and annealing in NH3 is considered to be connected with the generation of oxygen vacancies and the partial reduction of Pe(4+) to Pr3+. (C) 2014 Elsevier B.V. All rights reserved.

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