Speaker
Dr
ASHWINI SHARMA
(UNIVERSITY OF THE FREE STATE)
Description
Lanthanide ions (Ln3+) doped upconversion (UC) materials show great potential applications in optical and optoelectronic devices owing to their novel optical properties.Yb3+, Ho3+ co-doped NaGdF4 materials were synthesized by a simple co-precipitation method. Powder X-ray diffraction and X-ray photoelectron spectroscopy analysis demonstrated successful formation and incorporation of ions in NaGdF4: Yb3+, Ho3+ materials. The UC luminescence properties of NaGdF4 materials co- doped with different Yb3+, Ho3+ concentrations were investigated, and the related UC mechanisms of Yb3+, Ho3+ co-doped NaGdF4 depending on pump power were studied in detail.The intense green UC emission bands at 540, 549 nm, red emission at 645 nm and 752 nm signals in the emission spectra could be assigned to the 5S2, 5F4→5I8, 5F5 →5I8 and 5F4→5I7 transitions of Ho3+ via 980 nm near infrared excitation along with energy transfer from the Yb3+, respectively. It was confirmed that the green UC emission was generated via a two-photon process from a quadratic dependence of the emission intensity on the pumping power. The chromaticity coordinate (0.276, 0.708) of the optimized NaGdF4: 15 mol% Yb3+, 2 mol% Ho3+ upconversion material was located in the green region and hardly changed due to the negligible red emission. The present Yb3+, Ho3+ co-doped NaGdF4 phosphor is an interesting UC material with a stable crystal structure, good cytocompatibility and bioactivity possesses great potential for biomedical applications.
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Prof Hendrik C Swart
Department of Physics
University of the Free State,
Bloemfontein, Republic of South Africa
Email: swarthc@ufs.ac.za
| Consideration for<br>student awards<br><b>Choose one option<br>from those below.</b><br>N/A<br>Hons<br>MSc<br>PhD | N/A |
|---|---|
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Primary author
Dr
ASHWINI SHARMA
(UNIVERSITY OF THE FREE STATE)
Co-authors
Prof.
Hendrik Swart
(University of the Free State)
Prof.
JJ (Koos) Terblans
(UFS)
Prof.
Jorma Hölsä
(University of Turku)
Dr
S J DHOBLE
(R.T.M.NAGPUR UNIVERSITY, NAGPUR, INDIA)
Mr
Trilok Trilok Kumar Pathak
(Gurukula Kangri University, Haaridwar, India)
