Broad and intense NIR luminescence from rare earth doped SiO₂-Nb₂O₅ glass and glass ceramic prepared by a new sol gel route

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• 作者：Fá ; bio José ; Caixeta ; Felipe Thomaz Aquino ; Rafael Ramiro Pereira ; Rogé ; ria Rocha Gonç ; alves
• 关键词：Niobium oxide ; NIR emission ; Sol&ndash ; gel ; Lanthanides ; Photoluminescence spectroscopy
• 刊名：Journal of Luminescence
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：171
• 期：Complete
• 页码：63-71
• 全文大小：2056 K

文摘

A new sol–gel route was used for obtaining Er³⁺/Yb³⁺ co-doped Nb₂O₅ nanoparticles distributed in a SiO₂ based host. Phase separation and crystallization process were investigated for Er³⁺/Yb³⁺ co-doped nanocomposites at 70Si:30Nb molar ratio. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier transform infrared (FTIR), Raman, and Photoluminescence (PL) spectroscopy were used to assess the structural properties and their influence on luminescence. Amorphous Nb₂O₅ was identified after nanocomposite annealing at 700 °C, whereas at 900 °C and 1100 °C were identified both the orthorhombic and monoclinic phases. The average crystallite sizes were 6.6 nm at 900 °C and 16.4 nm at 1100 °C. Intense and broad NIR emission was observed for the nanocomposites annealed at 700 and 900 °C due to an efficient energy transfer from Yb³⁺ to Er³⁺ ions. Intense emissions at 980 nm and 1550 nm were also observed due to energy transfer from the host to Yb³⁺ and Er³⁺ ions, respectively. Additionally, a less efficient back energy transfer from Er³⁺ to Yb³⁺ ions was observed. The emission intensity and bandwidth were dependent on the nature of Nb₂O₅ crystalline phase, indicating that rare-earth (RE) ions are mostly distributed into Nb₂O₅ nanoparticles. The ⁴I_13/2 and ²F_5/2 excited state lifetimes were also dependent on Nb₂O₅ crystalline phase with shorter values for monoclinic Nb₂O₅. The featured luminescent properties exhibited by the rare earth-doped Nb₂O₅ make the nanocomposite materials potential candidates in many photonic applications.