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Optical property evaluation of thoria doped with heavier rare‐earth oxides LnO 1.5 (Ln = Er 3+ , Ho 3+ , Tm 3+ , and Yb 3+ )
Author(s) -
Kumar Manish,
Pokhriyal Meenakshi,
Gupta Mohini,
Vijaya Prakash Gaddam,
Uma Sitharaman,
Nagarajan Rajamani
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16053
Subject(s) - photon upconversion , analytical chemistry (journal) , materials science , lanthanide , doping , calcination , fluorite , emission spectrum , raman spectroscopy , spectral line , chemistry , ion , optics , physics , biochemistry , optoelectronics , organic chemistry , chromatography , catalysis , astronomy , metallurgy
To address the existing gap in the literature of upconversion studies involving thoria, samples of thoria doped with Ho 3+ ‐Yb 3+ , Er 3+ ‐Yb 3+ , and Tm 3+ ‐Yb 3+ were synthesized following epoxide gel method and were characterized. Fluorite structure of the doped samples was evident for the calcined samples from the corresponding xerogels as noticed in their powder X‐ray diffraction patterns. The presence of a sharp band near 460 cm −1 in the Raman spectra of all these samples supported the results from diffraction experiments. Intraconfigurational f‐f transitions of Ho 3+ , Er 3+ , and Tm 3+ were present in the UV ‐visible absorbance spectra of these samples. Both normal emission and upconversion emission from these samples have been studied. Emissions in all three basic colors were observed in the upconversion emission spectra. Two‐photon process was found to be responsible for the upconversion in these systems. Decay time measurements for these emissions were analyzed. This synthetic process was further extended to determine the extent of dissolution of heavier lanthanides and found that up to 50 mol% of Ho 3+ , Er 3+ and 60 mol% of Tm 3+ , Yb 3+ could be dissolved retaining fluorite structure. Creation of oxygen vacancies for these heavily doped specimens was quite encouraging and it could be useful as solid electrolytes in fuel cells.