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Ogugua SN, Abram C, Fond B, Kroon RE, Beyrau F, Swart HC. Effect of annealing conditions on the luminescence properties and thermometric performance of Sr 3Al 2O 5Cl 2:Eu 2+ and SrAl 2O 4:Eu 2+ phosphors. Dalton Trans 2024; 53:4551-4563. [PMID: 38349055 DOI: 10.1039/d3dt03836j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
We report on the synthesis, photoluminescence optimization and thermometric properties of Sr3Al2O5Cl2:Eu2+ and SrAl2O4:Eu2+ phosphor powders. The photoluminescence of Sr2.9Al2O5Cl2:0.1Eu2+ phosphors exhibits a blue-shift with an increasing annealing temperature owing to a decrease in the crystal field strength of the host caused by evaporation of Cl from the material. The quenching of the blue band in favour of the red band observed in the luminescence spectra of Sr2.9Al2O5Cl2:0.1Eu2+ with an increased annealing temperature was explained using the mechanism of the Landau-Zener transitions. The quantum yield and the lifetime of the phosphors depend on the annealing temperature. Phosphor samples annealed at 850 °C, 1000 °C, 1200 °C and 1500 °C were found to be potential luminescence thermometers using the luminescence spectral method. For Sr3Al2O5Cl2:Eu2+ annealed at 1000 °C, the temperature-dependent dual-band intensity ratio demonstrated a high-temperature sensitivity of ∼1.47%/°C in the temperature range of 23 °C to 40 °C which is superior to other reported phosphors with a microsecond decay time, suggesting that the material has potential for sensitive thermometry applications at ambient temperatures.
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Affiliation(s)
- Simon N Ogugua
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa.
| | - Christopher Abram
- Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544, USA.
| | - Benoît Fond
- Department of Aeronautics, ONERA the French Aerospace Lab, 92190 Meudon, France.
| | - Robin E Kroon
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa.
| | - Frank Beyrau
- Lehrstuhl für Technische Thermodynamik, Otto-von-Guericke-Universität Magdeburg, 39106 Magdeburg, Germany.
| | - Hendrik C Swart
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa.
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Ibáñez J, Sans JÁ, Cuenca-Gotor V, Oliva R, Gomis Ó, Rodríguez-Hernández P, Muñoz A, Rodríguez-Mendoza U, Velázquez M, Veber P, Popescu C, Manjón FJ. Structural and Lattice-Dynamical Properties of Tb 2O 3 under Compression: A Comparative Study with Rare Earth and Related Sesquioxides. Inorg Chem 2020; 59:9648-9666. [PMID: 32584569 PMCID: PMC7588034 DOI: 10.1021/acs.inorgchem.0c00834] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a joint experimental and theoretical investigation of the high pressure structural and vibrational properties of terbium sesquioxide (Tb2O3). Powder X-ray diffraction and Raman scattering measurements show that cubic Ia3̅ (C-type) Tb2O3 undergoes two phase transitions up to 25 GPa. We observe a first irreversible reconstructive transition to the monoclinic C2/m (B-type) phase at ∼7 GPa and a subsequent reversible displacive transition from the monoclinic to the trigonal P3̅m1 (A-type) phase at ∼12 GPa. Thus, Tb2O3 is found to follow the well-known C → B → A phase transition sequence found in other cubic rare earth sesquioxides with cations of larger atomic mass than Tb. Our ab initio theoretical calculations predict phase transition pressures and bulk moduli for the three phases in rather good agreement with experimental results. Moreover, Raman-active modes of the three phases have been monitored as a function of pressure, while lattice-dynamics calculations have allowed us to confirm the assignment of the experimental phonon modes in the C- and A-type phases as well as to make a tentative assignment of the symmetry of most vibrational modes in the B-type phase. Finally, we extract the bulk moduli and the Raman-active mode frequencies together with their pressure coefficients for the three phases of Tb2O3. These results are thoroughly compared and discussed in relation to those reported for rare earth and other related sesquioxides as well as with new calculations for selected sesquioxides. It is concluded that the evolution of the volume and bulk modulus of all the three phases of these technologically relevant compounds exhibit a nearly linear trend with respect to the third power of the ionic radii of the cations and that the values of the bulk moduli for the three phases depend on the filling of the f orbitals.
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Affiliation(s)
- Jordi Ibáñez
- Institute of Earth Sciences Jaume Almera, MALTA Consolider Team, Consell Superior d'Investigacions Científiques (CSIC), 08028 Barcelona, Catalonia, Spain
| | - Juan Ángel Sans
- Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València, Spain
| | - Vanesa Cuenca-Gotor
- Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València, Spain
| | - Robert Oliva
- Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland
| | - Óscar Gomis
- MALTA Consolider Team, Universitat Politècnica de València, 46022 València, Spain
| | - Plácida Rodríguez-Hernández
- Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de la Laguna, Tenerife, Spain
| | - Alfonso Muñoz
- Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de la Laguna, Tenerife, Spain
| | - Ulises Rodríguez-Mendoza
- Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de la Laguna, Tenerife, Spain
| | - Matías Velázquez
- University of Grenoble Alpes, CNRS, Grenoble INP, SIMAP, 38000 Grenoble, France
| | - Philippe Veber
- CNRS, Institut Lumière Matière, Université Claude Bernard Lyon 1, UMR5306, 69622 Villeurbanne, France
| | - Catalin Popescu
- ALBA-CELLS, MALTA Consolider Team, 08290 Cerdanyola del Vallès (Barcelona), Catalonia, Spain
| | - Francisco Javier Manjón
- Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València, Spain
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Vegas A, Jenkins HDB. Rationalization of the crystal structure of eudidymite Na 2Be 2[Si [4]6O 15]·H 2O in light of the extended Zintl-Klemm concept. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2020; 76:41-46. [PMID: 32831239 DOI: 10.1107/s205252061901549x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/15/2019] [Indexed: 06/11/2023]
Abstract
The structure of eudidymite is described in light of the extended Zintl-Klemm concept which considers that Na and Be atoms transfer their six valence electrons to the six Si atoms, converting them into Ψ-P which forms a skeleton characteristic of pentels (Group 15 elements) and is similar to that described in the compound (NH4)2Ge[6][Ge[4]6O15] when analysed in the same manner. The Si[4] skeleton is formed of bilayers that are connected through Be2O6 groups which are in fact fragments of the β-BeO structure which bridge the two contiguous Si-bilayers by sharing O atoms. In this context, the Be atoms play a dual role, i.e. on the one hand converting the Si atoms into Ψ-P, on the other hand replicating fragments of its own β-BeO structure. The Be atoms partially reproduce their own structure despite it being enclosed in a more complex network such as in Na2Be2[Si[4]6O15]·H2O. Calculations of the ionic strength I considering Si as Ψ-P is energetically more favourable than when I is calculated on the basis of tetravalent Si in the silicate, justifying this new approach of developing the theory of pseudo-structure generation. This approach offers a major new development in the study of crystal structures.
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Affiliation(s)
- Angel Vegas
- Universidad de Burgos, Hospital del Rey, s/n, Burgos, 09001, Spain
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Dalvit C, Vulpetti A. Weak Intermolecular Hydrogen Bonds with Fluorine: Detection and Implications for Enzymatic/Chemical Reactions, Chemical Properties, and Ligand/Protein Fluorine NMR Screening. Chemistry 2016; 22:7592-601. [DOI: 10.1002/chem.201600446] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Claudio Dalvit
- Faculty of Science University of Neuchâtel 2000 Neuchâtel Switzerland
- Sanofi, LG-CR/SDI/SBB 94403 Vitry-sur-Seine France
| | - Anna Vulpetti
- Novartis Institutes for Biomedical Research, Global Discovery Chemistry, CADD 4002 Basel Switzerland
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Wu C, Feng F, Xie Y. Design of vanadium oxide structures with controllable electrical properties for energy applications. Chem Soc Rev 2013; 42:5157-83. [DOI: 10.1039/c3cs35508j] [Citation(s) in RCA: 347] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Vegas Á, Liebman JF, Jenkins HDB. Unique thermodynamic relationships for Δf
H
o and Δf
G
o for crystalline inorganic salts. I. Predicting the possible existence and synthesis of Na2SO2 and Na2SeO2. ACTA CRYSTALLOGRAPHICA SECTION B: STRUCTURAL SCIENCE 2012; 68:511-27. [DOI: 10.1107/s0108768112030686] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/05/2012] [Indexed: 11/10/2022]
Abstract
The concept that equates oxidation and pressure has been successfully utilized in explaining the structural changes observed in the M
2S subnets of M
2SO
x
(x = 3, 4) compounds (M = Na, K) when compared with the structures (room- and high-pressure phases) of their parent M
2S `alloy' [Martínez-Cruz et al. (1994), J. Solid State Chem.
110, 397–398; Vegas (2000), Crystallogr. Rev.
7, 189–286; Vegas et al. (2002), Solid State Sci.
4, 1077–1081]. These structural changes suggest that if M
2SO2 would exist, its cation array might well have an anti-CaF2 structure. On the other hand, in an analysis of the existing thermodynamic data for M
2S, M
2SO3 and M
2SO4 we have identified, and report, a series of unique linear relationships between the known Δf
H
o and Δf
G
o values of the alkali metal (M) sulfide (x = 0) and their oxyanion salts M
2SO
x
(x = 3 and 4), and the similarly between M
2S2 disulfide (x = 0) and disulfur oxyanion salts M
2S2O
x
(x = 3, 4, 5, 6 and 7) and the number of O atoms in their anions x. These linear relationships appear to be unique to sulfur compounds and their inherent simplicity permits us to interpolate thermochemical data (Δf
H
o) for as yet unprepared compounds, M
2SO (x = 1) and M
2SO2 (x = 2). The excellent linearity indicates the reliability of the interpolated data. Making use of the volume-based thermodynamics, VBT [Jenkins et al. (1999), Inorg. Chem.
38, 3609–3620], the values of the absolute entropies were estimated and from them, the standard Δf
S
o values, and then the Δf
G
o values of the salts. A tentative proposal is made for the synthesis of Na2SO2 which involves bubbling SO2 through a solution of sodium in liquid ammonia. For this attractive thermodynamic route, we estimate ΔG
o to be approximately −500 kJ mol−1. However, examination of the stability of Na2SO2 raises doubts and Na2SeO2 emerges as a more attractive target material. Its synthesis is likely to be easier and it is stable to disproportionation into Na2S and Na2SeO4. Like Na2SO2, this compound is predicted to have an anti-CaF2 Na2Se subnet.
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Vegas A. On the charge transfer between conventional cations: the structures of ternary oxides and chalcogenides of alkali metals. ACTA CRYSTALLOGRAPHICA SECTION B: STRUCTURAL SCIENCE 2012; 68:364-77. [PMID: 22810906 DOI: 10.1107/s0108768112021234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 05/10/2012] [Indexed: 11/10/2022]
Abstract
The structures of ternary oxides and chalcogenides of alkali metals are dissected in light of the extended Zintl-Klemm concept. This model, which has been successfully extended to other compounds different to the Zintl phases, assumes that crystal structures can be better understood if the cation substructures are contemplated as Zintl polyanions. This implies the occurrence of charge transfer between cations, even if they are of the same kind. In this article, the charge transfer between cations is even more illustrative because the two alkali atoms have different electronegativity, so that the less electropositive alkali metal and the O/S atom always form skeletons characteristic of the group 14 elements. Thus, partial structures of the zincblende-, wurtzite-, PbO- and SrAl(2)-type are found in the oxides/sulfides. In this work, such an interpretation of the structures remains at a topological level. The analysis also shows that this interpretation is complementary to the model developed by Andersson and Hyde which contemplates the structures as the intergrowth of structural slabs of more simple compounds.
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Affiliation(s)
- Angel Vegas
- Universidad de Burgos, Parque Científico y Tecnológico, Edificio I+D+I, Plaza Misael Bañuelos, s/n, 09001 Burgos, Spain.
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Merging boron solid state and molecular chemistry: Energy landscapes in the exo/endo closo-borane complex Sc[B24H24]+. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.02.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Blatov VA. Crystal Structures of Inorganic Oxoacid Salts Perceived as Cation Arrays: A Periodic-Graph Approach. INORGANIC 3D STRUCTURES 2011. [DOI: 10.1007/430_2010_34] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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