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Thermally Induced Disorder–Order Phase Transition of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles and Its Implication on Photo- and Radioluminescence
[Image: see text] Crystal structure has a strong influence on the luminescence properties of lanthanide-doped materials. In this work, we have investigated the thermally induced structural transition in Gd(2)Hf(2)O(7) (GHO) using Eu(3+) ions as the spectroscopic probe. It was found that complete pha...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648517/ https://www.ncbi.nlm.nih.gov/pubmed/31459510 http://dx.doi.org/10.1021/acsomega.8b03458 |
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author | Gupta, Santosh K. Abdou, Maya Ghosh, Partha Sarathi Zuniga, Jose P. Mao, Yuanbing |
author_facet | Gupta, Santosh K. Abdou, Maya Ghosh, Partha Sarathi Zuniga, Jose P. Mao, Yuanbing |
author_sort | Gupta, Santosh K. |
collection | PubMed |
description | [Image: see text] Crystal structure has a strong influence on the luminescence properties of lanthanide-doped materials. In this work, we have investigated the thermally induced structural transition in Gd(2)Hf(2)O(7) (GHO) using Eu(3+) ions as the spectroscopic probe. It was found that complete phase transition from the disordered fluorite phase (DFP) to the ordered pyrochlore phase (OPP) can be achieved in GHO with the increase of annealing temperature from 650 → 1100 → 1300 °C. OPP is the more stable structural form for the GHOE nanoparticles (NPs) annealed at a higher temperature based on the energy calculation by density functional theory (DFT). The asymmetry ratio of the GHOE-650 NPs was the highest, whereas the quantum yield, luminescence intensity, and lifetime values of the GHOE-1300 NPs were the highest. Emission intensity of Eu(3+) ions increases significantly with the phase transition from the DFP to OPP phase and is attributed to the higher radiative transition rate (281 s(–1)) of the (5)D(0) level of the Eu(3+) ion in the environment with relatively lower symmetry (C(2v)) because of the increase of crystal size. As the structure changes from DFP to OPP, radioluminescence showed tunable color change from red to orange. The Eu(3+) local structure obtained from DFT calculation confirmed the absence of inversion symmetry in the DFP structure, which is consistent with the experimental emission spectra and Stark components. We also elucidated the host to dopant optical energy transfer through density of states calculations. Overall, our current studies present important observations for the GHOE NPs: (i) thermally induced order–disorder phase transition, (ii) change of point group symmetry around Eu(3+) ions in the two phases, (iii) high thermal stability, and (iv) tunability of radioluminescent color. This work provides fundamental understanding of the relationship between the crystal structure and photophysical properties of lanthanide-doped materials and helps design a strategy for advanced optoelectronic materials. |
format | Online Article Text |
id | pubmed-6648517 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-66485172019-08-27 Thermally Induced Disorder–Order Phase Transition of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles and Its Implication on Photo- and Radioluminescence Gupta, Santosh K. Abdou, Maya Ghosh, Partha Sarathi Zuniga, Jose P. Mao, Yuanbing ACS Omega [Image: see text] Crystal structure has a strong influence on the luminescence properties of lanthanide-doped materials. In this work, we have investigated the thermally induced structural transition in Gd(2)Hf(2)O(7) (GHO) using Eu(3+) ions as the spectroscopic probe. It was found that complete phase transition from the disordered fluorite phase (DFP) to the ordered pyrochlore phase (OPP) can be achieved in GHO with the increase of annealing temperature from 650 → 1100 → 1300 °C. OPP is the more stable structural form for the GHOE nanoparticles (NPs) annealed at a higher temperature based on the energy calculation by density functional theory (DFT). The asymmetry ratio of the GHOE-650 NPs was the highest, whereas the quantum yield, luminescence intensity, and lifetime values of the GHOE-1300 NPs were the highest. Emission intensity of Eu(3+) ions increases significantly with the phase transition from the DFP to OPP phase and is attributed to the higher radiative transition rate (281 s(–1)) of the (5)D(0) level of the Eu(3+) ion in the environment with relatively lower symmetry (C(2v)) because of the increase of crystal size. As the structure changes from DFP to OPP, radioluminescence showed tunable color change from red to orange. The Eu(3+) local structure obtained from DFT calculation confirmed the absence of inversion symmetry in the DFP structure, which is consistent with the experimental emission spectra and Stark components. We also elucidated the host to dopant optical energy transfer through density of states calculations. Overall, our current studies present important observations for the GHOE NPs: (i) thermally induced order–disorder phase transition, (ii) change of point group symmetry around Eu(3+) ions in the two phases, (iii) high thermal stability, and (iv) tunability of radioluminescent color. This work provides fundamental understanding of the relationship between the crystal structure and photophysical properties of lanthanide-doped materials and helps design a strategy for advanced optoelectronic materials. American Chemical Society 2019-02-06 /pmc/articles/PMC6648517/ /pubmed/31459510 http://dx.doi.org/10.1021/acsomega.8b03458 Text en Copyright © 2019 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Gupta, Santosh K. Abdou, Maya Ghosh, Partha Sarathi Zuniga, Jose P. Mao, Yuanbing Thermally Induced Disorder–Order Phase Transition of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles and Its Implication on Photo- and Radioluminescence |
title | Thermally Induced Disorder–Order Phase Transition
of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles
and Its Implication on Photo- and Radioluminescence |
title_full | Thermally Induced Disorder–Order Phase Transition
of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles
and Its Implication on Photo- and Radioluminescence |
title_fullStr | Thermally Induced Disorder–Order Phase Transition
of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles
and Its Implication on Photo- and Radioluminescence |
title_full_unstemmed | Thermally Induced Disorder–Order Phase Transition
of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles
and Its Implication on Photo- and Radioluminescence |
title_short | Thermally Induced Disorder–Order Phase Transition
of Gd(2)Hf(2)O(7):Eu(3+) Nanoparticles
and Its Implication on Photo- and Radioluminescence |
title_sort | thermally induced disorder–order phase transition
of gd(2)hf(2)o(7):eu(3+) nanoparticles
and its implication on photo- and radioluminescence |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648517/ https://www.ncbi.nlm.nih.gov/pubmed/31459510 http://dx.doi.org/10.1021/acsomega.8b03458 |
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