Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles
Tetragonal Er<sub>0.5</sub>Nb<sub>0.5</sub>O<sub>2</sub> and monoclinic ErNbO<sub>4</sub> micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO<sub>4</sub> revea...
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MDPI AG
2021-03-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/3/660 |
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| author | Susana Devesa Joana Rodrigues Sílvia Soreto Teixeira Aidan P. Rooney Manuel P. F. Graça David Cooper Teresa Monteiro Luís C. Costa |
| author_facet | Susana Devesa Joana Rodrigues Sílvia Soreto Teixeira Aidan P. Rooney Manuel P. F. Graça David Cooper Teresa Monteiro Luís C. Costa |
| author_sort | Susana Devesa |
| collection | DOAJ |
| description | Tetragonal Er<sub>0.5</sub>Nb<sub>0.5</sub>O<sub>2</sub> and monoclinic ErNbO<sub>4</sub> micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO<sub>4</sub> revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. To assess their optical properties at room temperature (RT), a thorough spectroscopic study was conducted. RT photoluminescence (PL) spectroscopy revealed that Er<sup>3+</sup> optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow <sup>2</sup>H<sub>11/2</sub>, <sup>4</sup>S<sub>3/2</sub>→<sup>4</sup>I<sub>15/2</sub> and red <sup>4</sup>F<sub>9/2</sub>→<sup>4</sup>I<sub>15/2</sub> intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er<sup>3+</sup> multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er<sup>3+</sup> high-energy excited multiplets as the preferential population paths of the emitting levels. Independently of the crystalline structure, the intensity ratio between the green/yellow and red intraionic transitions was found to be strongly sensitive to the excitation energy. After pumping the samples with a resonant excitation into the <sup>4</sup>G<sub>11/2</sub> excited multiplet, a green/yellow transition stronger than the red one was observed, whereas the reverse occurred for higher excitation photon energies. Thus, a controllable selective excited tunable green to red color was achieved, which endows new opportunities for photonic and optoelectronic applications. |
| first_indexed | 2024-03-10T13:26:49Z |
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| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T13:26:49Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
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| series | Nanomaterials |
| spelling | doaj.art-26fe1eed37754dc6bfd819beb40355c62023-11-21T09:35:36ZengMDPI AGNanomaterials2079-49912021-03-0111366010.3390/nano11030660Tuning Green to Red Color in Erbium Niobate Micro- and NanoparticlesSusana Devesa0Joana Rodrigues1Sílvia Soreto Teixeira2Aidan P. Rooney3Manuel P. F. Graça4David Cooper5Teresa Monteiro6Luís C. Costa7Centre for Physics University of Coimbra (CFisUC), Physics Department, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugali3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugali3N and Physics Department, University of Aveiro, 3810-193 Aveiro, PortugalCEA LETI-Minatec, 17 Rue des Martyrs, 38054 Grenoble CEDEX 9, Francei3N and Physics Department, University of Aveiro, 3810-193 Aveiro, PortugalCEA LETI-Minatec, 17 Rue des Martyrs, 38054 Grenoble CEDEX 9, Francei3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugali3N and Physics Department, University of Aveiro, 3810-193 Aveiro, PortugalTetragonal Er<sub>0.5</sub>Nb<sub>0.5</sub>O<sub>2</sub> and monoclinic ErNbO<sub>4</sub> micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO<sub>4</sub> revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. To assess their optical properties at room temperature (RT), a thorough spectroscopic study was conducted. RT photoluminescence (PL) spectroscopy revealed that Er<sup>3+</sup> optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow <sup>2</sup>H<sub>11/2</sub>, <sup>4</sup>S<sub>3/2</sub>→<sup>4</sup>I<sub>15/2</sub> and red <sup>4</sup>F<sub>9/2</sub>→<sup>4</sup>I<sub>15/2</sub> intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er<sup>3+</sup> multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er<sup>3+</sup> high-energy excited multiplets as the preferential population paths of the emitting levels. Independently of the crystalline structure, the intensity ratio between the green/yellow and red intraionic transitions was found to be strongly sensitive to the excitation energy. After pumping the samples with a resonant excitation into the <sup>4</sup>G<sub>11/2</sub> excited multiplet, a green/yellow transition stronger than the red one was observed, whereas the reverse occurred for higher excitation photon energies. Thus, a controllable selective excited tunable green to red color was achieved, which endows new opportunities for photonic and optoelectronic applications.https://www.mdpi.com/2079-4991/11/3/660erbium niobatesol–gelPLPLETRPL |
| spellingShingle | Susana Devesa Joana Rodrigues Sílvia Soreto Teixeira Aidan P. Rooney Manuel P. F. Graça David Cooper Teresa Monteiro Luís C. Costa Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles Nanomaterials erbium niobate sol–gel PL PLE TRPL |
| title | Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles |
| title_full | Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles |
| title_fullStr | Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles |
| title_full_unstemmed | Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles |
| title_short | Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles |
| title_sort | tuning green to red color in erbium niobate micro and nanoparticles |
| topic | erbium niobate sol–gel PL PLE TRPL |
| url | https://www.mdpi.com/2079-4991/11/3/660 |
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