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Near-infrared emission and upconversion in nanocrystalline Er3+/Ho3+-doped Yb3Ga5O12 garnet

Authors: Netolický Tomáš | Beneš Ludvík | Melánová Klára | Šlang Stanislav | Oswald J. | Wágner Tomáš

Year: 2022

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Near-infrared emission and upconversion in nanocrystalline Er3+/Ho3+-doped Yb3Ga5O12 garnet	Nanocrystalline oxide of composition Yb3Ga5O12 belongs to the family of materials with garnet-related structure (space group Ia-3d). It is a promising material with potential applications in the fields of optics and photonics when doped by Er3+ or Ho3+ ions. High content of Yb3+ ions in the Yb15-xErxGa25O60 and Yb15-xHoxGa25O60 hosts results in strong absorption band observed from ≈850 to ≈1050 nm due to the Yb3+: 2F7/2 → 2F5/2 transition. Excitation using ≈980 nm laser leads to efficient energy transfer from the Yb3+ ions to the neighbouring Er3+/Ho3+ ions. Subsequent radiative transition of Er3+/Ho3+ ions from the upper- and lower-lying excited energy levels provide emission bands observed in visible and near-infrared region, respectively. Nanocrystals of composition Yb15-xErxGa25O60 and Yb15-xHoxGa25O60 (with x = 0, 0.01, 0.1, 0.5, 1 and 2 at.%) were prepared by sol-gel combustion technique using citric acid as chelation agent. Phase composition and morphology of the annealed powders were studied by X-ray diffraction and by scanning electron microscopy. Optical reflectance of the powders and absorption bands of present lanthanides were investigated by diffuse reflectance spectroscopy. Photoluminescence spectroscopy was used for measurement of the steady-state and time-dependent Er3+ and Ho3+ emission spectra. Near-infrared (Stokes) and upconversion (anti-Stokes) emission mechanisms are proposed using energy level diagrams of the Yb3+, Er3+ and Ho3+ ions.	Near-infrared; emission; and; upconversion; nanocrystalline; Er3+/Ho3+-doped; Yb3Ga5O12; garnet