Issue 27, 2016

Defect induced tunable near infrared emission of Er–CeO2 by heterovalent co-dopants

Abstract

We investigate the effects of heterovalent co-dopants on the structural and emission properties of 1% Er–CeO2 nanoparticles. The CeO2 oxide host was selected on the basis of its fairly well-understood defect chemistry in either a pure or doped state. As a luminescent activator, Er is acknowledged as an interesting element due to its rich luminescence and excitation properties spanning the visible to near-infrared range. The optically inactive trivalent La and monovalent Li metal ions with a concentration of up to 20% were chosen to presumably generate a variable amount of defects in the Er–CeO2 lattice. It was found that La and Li co-dopants induced distinct changes related to the size, lattice constant, bandgap energy, lattice and surface defects of Er–CeO2. As a result of these changes, a strong modulation of the luminescence intensity and shape was measured using a suite of excitation conditions (charge-transfer absorption band of CeO2, direct/up-conversion into Er absorptions and X-ray excitation modes). The use of Eu as a luminescent probe offered additional information concerning the effects of La/Li co-doping on the local structure surrounding the luminescent activator. Remarkably high percentages of 90 and 98% of the total emission of Er measured between 500 and 1100 nm are measured in the near-infrared region at 980 nm under X-ray and up-conversion excitation at ∼1500 nm, respectively. The optical properties suggest that Li, Er co-doped CeO2 has good potential for therapy and biological imaging.

Graphical abstract: Defect induced tunable near infrared emission of Er–CeO2 by heterovalent co-dopants

Supplementary files

Article information

Article type
Paper
Submitted
25 Apr 2016
Accepted
03 Jun 2016
First published
03 Jun 2016

Phys. Chem. Chem. Phys., 2016,18, 18268-18277

Defect induced tunable near infrared emission of Er–CeO2 by heterovalent co-dopants

M. Florea, D. Avram, B. Cojocaru, I. Tiseanu, V. Parvulescu and C. Tiseanu, Phys. Chem. Chem. Phys., 2016, 18, 18268 DOI: 10.1039/C6CP02754G

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