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Devesa S, Rodrigues J, Teixeira SS, Rooney AP, Graça MPF, Cooper D, Monteiro T, Costa LC. Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles. NANOMATERIALS 2021; 11:nano11030660. [PMID: 33800356 PMCID: PMC7998491 DOI: 10.3390/nano11030660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 11/16/2022]
Abstract
Tetragonal Er0.5Nb0.5O2 and monoclinic ErNbO4 micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO4 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 Er3+ optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow 2H11/2, 4S3/2→4I15/2 and red 4F9/2→4I15/2 intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er3+ multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er3+ 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 4G11/2 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.
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Affiliation(s)
- Susana Devesa
- Centre for Physics University of Coimbra (CFisUC), Physics Department, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugal
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
- Correspondence: (S.D.); (J.R.); (T.M.); (L.C.C.); Tel.: +351-234-370-944 (S.D.); +351-234-247-261 (J.R.); +351-234-370-824 (T.M.); +351-234-370-944 (L.C.C.)
| | - Joana Rodrigues
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
- Correspondence: (S.D.); (J.R.); (T.M.); (L.C.C.); Tel.: +351-234-370-944 (S.D.); +351-234-247-261 (J.R.); +351-234-370-824 (T.M.); +351-234-370-944 (L.C.C.)
| | - Sílvia Soreto Teixeira
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
| | - Aidan P. Rooney
- CEA LETI-Minatec, 17 Rue des Martyrs, 38054 Grenoble CEDEX 9, France; (A.P.R.); (D.C.)
| | - Manuel P. F. Graça
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
| | - David Cooper
- CEA LETI-Minatec, 17 Rue des Martyrs, 38054 Grenoble CEDEX 9, France; (A.P.R.); (D.C.)
| | - Teresa Monteiro
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
- Correspondence: (S.D.); (J.R.); (T.M.); (L.C.C.); Tel.: +351-234-370-944 (S.D.); +351-234-247-261 (J.R.); +351-234-370-824 (T.M.); +351-234-370-944 (L.C.C.)
| | - Luís C. Costa
- i3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal; (S.S.T.); (M.P.F.G.)
- Correspondence: (S.D.); (J.R.); (T.M.); (L.C.C.); Tel.: +351-234-370-944 (S.D.); +351-234-247-261 (J.R.); +351-234-370-824 (T.M.); +351-234-370-944 (L.C.C.)
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Gao M, Pan Y, Jin Y, Lin J. A review on the structural dependent optical properties and energy transfer of Mn 4+ and multiple ion-codoped complex oxide phosphors. RSC Adv 2020; 11:760-779. [PMID: 35423701 PMCID: PMC8693397 DOI: 10.1039/d0ra08550b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/16/2020] [Indexed: 11/21/2022] Open
Abstract
The tetravalent manganese Mn4+ ions with a 3d3 electron configuration as luminescence centers in solid-state inorganic compounds have been widely investigated because they emit bright light in the red to far-red region when they are excited by light with a wavelength in the UV to blue light region. Herein, we present an overview of the recent developments of Mn4+ and multiple ion such as Bi3+ and rare earth ion Dy3+, Nd3+, Yb3+, Er3+, Ho3+, and Tm3+ codoped complex oxide phosphors. Most of the specified host lattices of these complex oxide phosphors possess multiple metallic cations, which provide possible substitutions with different codopants and form various luminescence centers with diverse spectra. The luminescence of Mn4+ and multiple ion-codoped materials spans almost the whole visible light to near infrared (NIR) region. The crystal structures of complex oxide phosphors, the spectroscopic properties of Mn4+, and the energy transfer between Mn4+ and multiple ions are introduced and summarized in detail with regard to their practical applications. This review provides an insight into the optical properties of Mn4+ and the energy transfer process in multiple ion-codoped luminescence materials, which will be helpful in the development of novel excellent materials for applications in the lighting industry.
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Affiliation(s)
- Meng Gao
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University Wenzhou 325035 P. R. China +86-577-88373017 +86-577-88373017
| | - Yuexiao Pan
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University Wenzhou 325035 P. R. China +86-577-88373017 +86-577-88373017
| | - Yitian Jin
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University Wenzhou 325035 P. R. China +86-577-88373017 +86-577-88373017
| | - Jun Lin
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China +86-431-85698041 +86-431-85262031
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A combined study of the thermoluminescence and electron paramagnetic resonance of point defects in ZrO2:Er3+. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Avram D, Colbea C, Florea M, Lazar S, Stroppa D, Tiseanu C. Imaging dopant distribution across complete phase transformation by TEM and upconversion emission. NANOSCALE 2019; 11:16743-16754. [PMID: 31403145 DOI: 10.1039/c9nr04345d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Correlating dopant distribution to its optical response represents a complex challenge for nanomaterials science. Differentiating the "true" clustering nature from dopant pairs formed in statistical distribution complicates even more the elucidation of doping-functionality relationship. The present study associates lanthanide dopant distribution, including all significant events (enrichment, depletion and surface segregation), to its optical response in upconversion (UPC) at the ensemble and single-nanoparticle level. A small deviation from the Er nominal concentration of a few percent is able to induce clear differences in Er UPC emission color, intensity, excited-state dynamics and ultimately, UPC mechanisms, across tetragonal to monoclinic phase transformation in rationally designed Er doped ZrO2 nanoparticles. Rare evidence of a heterogeneous dopant distribution leading to the coexistence of two polymorphs in a single nanoparticle is revealed by Z- and phase contrast transmission electron microscopy (TEM). Despite their spatial proximity, Er in the two polymorphs are spectroscopically isolated, i.e. they do not communicate by energy transfer. Segregated Er, which is well imaged in TEM, is absent in UPC, while the minor phase content overlooked by X-ray diffraction and TEM is revealed by UPC. The outstanding sensitivity of combined TEM and UPC emission to subtle deviations from uniform doping in the diluted concentration regime renders such an approach relevant for various functional oxides supporting lanthanide dopants as emitters.
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Affiliation(s)
- Daniel Avram
- National Institute for Laser, Plasma and Radiation Physics, P.O. Box MG-36, RO 76900, Bucharest-Magurele, Romania.
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Doped zirconia phase and luminescence dependence on the nature of charge compensation. Sci Rep 2017; 7:44453. [PMID: 28287623 PMCID: PMC5347385 DOI: 10.1038/srep44453] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/07/2017] [Indexed: 11/08/2022] Open
Abstract
Zirconia is a relatively new material with many promising practical applications in medical imaging, biolabeling, sensors, and other fields. In this study we have investigated lanthanide and niobium doped zirconia by luminescence and XRD methods. It was proven that charge compensation in different zirconia phases determines the incorporation of intrinsic defects and activators. Thus, the structure of zirconia does not affect the Er luminescence directly; however, it strongly affects the defect distribution around lanthanide ions and the way in which activator ions are incorporated in the lattice. Our results demonstrate the correlation between the crystalline phase of zirconia and charge compensation, as well as the contribution of different nanocrystal grain sizes. In addition, our experimental results verify the theoretical studies of metastable (tetragonal, cubic) phase stabilization determined using only oxygen vacancies. Moreover, it was found that adding niobium drastically increases activator luminescence intensity, which makes Ln3+ doped zirconia even more attractive for various practical applications. Although this study was based on the luminescence of the Er ion, the phase stabilization, charge compensation, and luminescence properties described in our results are expected to be similar for other lanthanide elements. Our results suggest that the luminescence intensity of other oxide matrices where lanthanides incorporate in place of tetravalent cations could be increased by addition of Nb ions.
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Azevedo SL, Holz T, Rodrigues J, Monteiro T, Costa FM, Soares AMVM, Loureiro S. A mixture toxicity approach to predict the toxicity of Ag decorated ZnO nanomaterials. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:337-344. [PMID: 27887838 DOI: 10.1016/j.scitotenv.2016.11.095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 10/28/2016] [Accepted: 11/15/2016] [Indexed: 05/24/2023]
Abstract
Nanotechnology is a rising field and nanomaterials can now be found in a vast variety of products with different chemical compositions, sizes and shapes. New nanostructures combining different nanomaterials are being developed due to their enhancing characteristics when compared to nanomaterials alone. In the present study, the toxicity of a nanostructure composed by a ZnO nanomaterial with Ag nanomaterials on its surface (designated as ZnO/Ag nanostructure) was assessed using the model-organism Daphnia magna and its toxicity predicted based on the toxicity of the single components (Zn and Ag). For that ZnO and Ag nanomaterials as single components, along with its mixture prepared in the laboratory, were compared in terms of toxicity to ZnO/Ag nanostructures. Toxicity was assessed by immobilization and reproduction tests. A mixture toxicity approach was carried out using as starting point the conceptual model of Concentration Addition. The laboratory mixture of both nanomaterials showed that toxicity was dependent on the doses of ZnO and Ag used (immobilization) or presented a synergistic pattern (reproduction). The ZnO/Ag nanostructure toxicity prediction, based on the percentage of individual components, showed an increase in toxicity when compared to the expected (immobilization) and dependent on the concentration used (reproduction). This study demonstrates that the toxicity of the prepared mixture of ZnO and Ag and of the ZnO/Ag nanostructure cannot be predicted based on the toxicity of their components, highlighting the importance of taking into account the interaction between nanomaterials when assessing hazard and risk.
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Affiliation(s)
- S L Azevedo
- Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - T Holz
- Physics Department, I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - J Rodrigues
- Physics Department, I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - T Monteiro
- Physics Department, I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - F M Costa
- Physics Department, I3N, University of Aveiro, 3810-193 Aveiro, Portugal
| | - A M V M Soares
- Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - S Loureiro
- Department of Biology, CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
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Soares MRN, Ferro M, Costa FM, Monteiro T. Upconversion luminescence and blackbody radiation in tetragonal YSZ co-doped with Tm(3+) and Yb(3+). NANOSCALE 2015; 7:19958-19969. [PMID: 26469333 DOI: 10.1039/c5nr04052c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Lanthanide doped inorganic nanoparticles with upconversion luminescence are of utmost importance for biomedical applications, solid state lighting and photovoltaics. In this work we studied the downshifted luminescence, upconversion luminescence (UCL) and blackbody radiation of tetragonal yttrium stabilized zirconia co-doped with Tm(3+) and Yb(3+) single crystals and nanoparticles produced by laser floating zone and laser ablation in liquids, respectively. The photoluminescence (PL) and PL excitation (PLE) were investigated at room temperature (RT). PL spectra exhibit the characteristic lines in UV, blue/green, red and NIR regions of the Tm(3+) (4f(12)) under resonant excitation into the high energy (2S+1)LJ multiplets. Under NIR excitation (980 nm), the samples placed in air display an intense NIR at ∼800 nm due to the (1)G4→(3)H5/(3)H4→(3)H6 transitions. Additionally, red, blue/green and ultraviolet UCL is observed arising from higher excited (1)G4 and (1)D2 multiplets. The power excitation dependence of the UCL intensity indicated that 2-3 low energy absorbed photons are involved in the UCL for low power levels, while for high powers, the identified saturation is dependent on the material size with a enhanced effect on the NPs. The temperature dependence of the UCL was investigated for single crystals and targets used in the ablation. An overall increase of the integrated intensity was found to occur between 12 K and the RT. The thermally activated process is described by activation energies of 10 meV and 30 meV for single crystals and targets, respectively. For the NPs, the UCL was found to be strongly sensitive to pressure conditions. Under vacuum conditions, instead of the narrow lines of the Tm(3+), a wide blackbody radiation was detected, responsible for the change in the emission colour from blue to orange. This phenomenon is totally reversible when the NPs are placed at ambient pressure. The UCL/blackbody radiation in the nanosized material exhibits non-contact pressure colour-based sensor characteristics. Moreover, tuning the color of the blackbody radiation in the nanoparticles by harvesting the low energy photons into the visible spectral region was found to be possible by adjusting the excitation power, paving the way for further developments of these nanoparticles for lighting and photovoltaic applications.
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Affiliation(s)
- M R N Soares
- Departamento de Física & I3N, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
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