Structural, photoluminescent properties and Judd-Ofelt analysis of Eu3+-activated CaF2 nanocubes

JOURNAL OF ALLOYS AND COMPOUNDS

卷:813

Review

Cantelar, Eugenio¹  Antonio Sanz-Garcia, Juan¹  Sanz-Martin, Adrian¹  Munoz Santiuste, Juan Enrique²  Cusso, Fernando¹ 

[1] Univ Autonoma Madrid, Fac Ciencias, Dept Fis Mat, Avda Francisco Tomas y Valiente 7,C-04, E-28049 Madrid, Spain

[2] Univ Carlos III Madrid, Escuela Politecn Super, Dept Fis, Madrid, Spain

关键词: CaF2 nanoparticles;    Eu3+;    Rietveld refinement;    Judd-Ofelt;    Concentration dependence;   

DOI  :  10.1016/j.jallcom.2019.152194

来源: Elsevier

【 摘 要 】

Eu3+-doped CaF2 nanocubes with variable europium concentration, [Eu3+] = 0, 0.6, 1.3, 1.7, 2.2 and 5.4 mol%, have been synthesized by a direct precipitation route. It has been found that, within this concentration range, the nanoparticles present the fluoride-type crystalline structure and the characteristic cubic shape of CaF2 crystals. The nanoparticle size follows a log-normal distribution with a mean value decreasing with the Eu3+ content. Rietveld refinement has been performed to calculate the lattice parameter and crystallite size. Eu3+ concentration affects both parameters giving rise to an increase in the lattice parameter and a reduction of crystallite size. The luminescent properties of Eu3+ ions in these nanostructures have been investigated under CWand pulsed excitation. A Judd-Ofelt analysis, as function of the Eu3+ content, has been performed to determine the transition probabilities, radiative lifetimes and branching ratios of the D-5(0) emitting level. It was found that Omega(2) and Omega(4) Judd-Ofelt intensity parameters are dependent on the doping level, showing an evolution that indicates a decrease in the Eu3+ site local symmetry with increasing Eu3+ concentration. Finally, it has been observed that the characteristic luminescence decay time of the D-5(0) manifold is reduced with increasing Eu3+ concentration. This effect is partially due to an increase of radiative transition probability, associated with a reduction in the local symmetry of the lanthanide ions, and also to the occurrence of concentration quenching effects. (C) 2019 The Authors. Published by Elsevier B.V.

【 授权许可】

Free