Er

Luminescence of Er/Yb and Tm/Yb doped FAp nanoparticles and ceramics

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L. Grigorjeva, K. Smits, D.Millers, Dz.Jankoviča

Abstract. The nanoparticles of hydroxiapatite and fluorapatite doped with
Er/Yb and Tm/Yb were synthesized and characterized by FTIR, XRD, SEM and
TEM methods. The results of up-conversion luminescence studies were
presented for the samples as prepared, annealed at 500°C and at 900-1000 °C.
At annealing above 800°C the ceramic state was formed. It is shown that
fluorapatite host is more appropriate than hydroxiapatite host for rare ions
luminescence and up-conversion processes. The post preparing annealing of
nanarticles significantly enhanced the luminescence intensity. The Tm/Yb
doped fluorapatite shows intense up-conversion luminescence in 790-800 nm
spectral region and is potentially useful for biomedical applications.

IOP Conference Series: Materials Science and Engineering 77 (2015) 012036

doi:10.1088/1757-899X/77/1/012036

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The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

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K. Smits, A. Sarakovskis, L. Grigorjeva, D. Millers, and J. Grabis

It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity
in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb
co-doping were prepared by sol-gel method and thermally annealed to check for the impact of
phase transition on luminescence properties. Phase composition and grain sizes were examined by
X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission
electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison
of samples with different oxygen vacancy concentrations and different Nb concentrations
confirmed the known assumption that oxygen vacancies are the main agents for tetragonal or cubic
phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they
also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain
surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion
luminescence intensity. Hence, ZrO2:Er:Yb:Nb nanocrystals may show promise for upconversion
applications

Journal of Applied Physics 115, 213520 (2014)

DOI:10.1063/1.4882262

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The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

Posted on by editor

K. Smits, A. Sarakovskis, L. Grigorjeva, D. Millers, J. Grabis

It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity
in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb
co-doping were prepared by sol-gel method and thermally annealed to check for the impact of
phase transition on luminescence properties. Phase composition and grain sizes were examined by
X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission
electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison
of samples with different oxygen vacancy concentrations and different Nb concentrations
confirmed the known assumption that oxygen vacancies are the main agents for tetragonal or cubic
phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they
also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain
surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion
luminescence intensity. Hence, ZrO2:Er:Yb:Nb nanocrystals may show promise for upconversion
applications.

VC 2014 AIP Publishing LLC.

doi: 10.1063/1.4882262

http://dx.doi.org/10.1063/1.4882262

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