Structural Properties Investigation of Different Alumina Polymorphs (η-, γ-, χ-, θ-, α-Al2O3) Using Cr3+ as a Luminescent Probe Full article
| Journal |
Journal of Luminescence
ISSN: 0022-2313 |
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| Output data | Year: 2022, Volume: 242, Article number : 118554, Pages count : 7 DOI: 10.1016/j.jlumin.2021.118554 | ||
| Tags | alumina polymorphs, luminescence, Cr3+ luminescent probe, structure | ||
| Authors |
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| Affiliations |
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Funding (2)
| 1 | Ministry of Science and Higher Education of the Russian Federation | 0239-2021-0003 |
| 2 | Ministry of Science and Higher Education of the Russian Federation | 0239-2021-0011 |
Abstract:
The structural properties of η-, γB-, γPb-, χ-, θ- and α-Al2O3 polymorphs were studied by X-ray diffraction and photoluminescence spectroscopy using Cr3+ ion as a luminescent probe in its natural concentration (<10−3 wt%). The analysis of photoluminescence (PL) and photoluminescence excitation (PLE) data within the crystal field theory revealed a decrease in the crystal field strength Dq from 1810 to 1740 cm−1, the Racah parameter B from 606 to 432 cm−1, and the covalence parameter β1 from 1.076 to 1.062 in the series α-Al2O3 → γ-, η-Al2O3. This indicates that the fraction of covalent bond increases for the low-temperature γ-Al2O3 and η-Al2O3 phases as compared to α-Al2O3 powder and ruby single crystal. The obtained values of crystal field strength Dq, Racah parameters B and C, and covalence degree β1 also differ from each other among low-temperature phases η-, γB-, γPb- and χ-Al2O3. This testifies that each low-temperature Al2O3 polymorph has different ionicity/covalence ratio. The analysis of PL and PLE data showed that the chromium ion in χ-Al2O3 occupies the local structural positions that are similar to those in α-Al2O3. This occurs because, according to XRD data, the cubic closest packing of oxygen anions in χ-Al2O3 partially transforms into the hexagonal closest packing, which is typical of α-Al2O3.
Cite:
Baronskiy M.G.
, Tsybulya S.V.
, Kostyukov A.I.
, Zhuzhgov A.V.
, Snytnikov V.N.
Structural Properties Investigation of Different Alumina Polymorphs (η-, γ-, χ-, θ-, α-Al2O3) Using Cr3+ as a Luminescent Probe
Journal of Luminescence. 2022. V.242. 118554 :1-7. DOI: 10.1016/j.jlumin.2021.118554 WOS Scopus РИНЦ AN OpenAlex
Structural Properties Investigation of Different Alumina Polymorphs (η-, γ-, χ-, θ-, α-Al2O3) Using Cr3+ as a Luminescent Probe
Journal of Luminescence. 2022. V.242. 118554 :1-7. DOI: 10.1016/j.jlumin.2021.118554 WOS Scopus РИНЦ AN OpenAlex
Dates:
| Submitted: | May 27, 2021 |
| Accepted: | Oct 23, 2021 |
| Published online: | Oct 26, 2021 |
| Published print: | Feb 1, 2022 |
Identifiers:
| Web of science: | WOS:000718510600005 |
| Scopus: | 2-s2.0-85117946903 |
| Elibrary: | 47518495 |
| Chemical Abstracts: | 2021:2340746 |
| OpenAlex: | W3208739762 |