Isolated centres versus defect associates in Sm<sup>3+</sup>-doped CeO<sub>2</sub>: a spectroscopic investigation

Tiseanu, Carmen; Cojocaru, Bogdan; Avram, Daniel; Pârvulescu, Vasile I.; Vela-Gonzalez, Andrea V.; Sánchez-Domínguez, Margarita

doi:10.1088/0022-3727/46/27/275302

Cited by 30 publications

(41 citation statements)

References 38 publications

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“…49 Both ratios steadily increase with the dopant content, corresponding to Sm 3+ in an asymmetric environment in the more concentrated samples. This is also in general agreement with the results from Raman, where lower sintering temperatures and higher doping levels result in a higher concentration of asymmetric or disordered sites.…”

Section: Chemistry Of Materialsmentioning

confidence: 94%

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

et al. 2014

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The long-range and short-range structure of nanocrystalline and microcrystalline acceptor-doped ceria is investigated by a combined approach using EXAFS, XANES, Raman, and XRD, and correlated with the oxide-ion conductivity in the bulk and in grain boundaries. Compared to Yb 3+ and Er 3+ , the positive influence of Sm 3+ is attributed to the ability to repel oxygen vacancies, and to keep a localized disorder around the dopant. The long-range structural analysis shows lattice contraction for Yband Er-doping and lattice expansion for Sm-doping. The short-range analysis around the dopants and cerium highlights that a more complex structural rearrangement has to be assumed to explain the complementary results of the different techniques. Nominally trivalent dopants are also shown to have an effect on the electronic structure of ceria, and the consequences on oxide-ion conductivity are highlighted.

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Section: Chemistry Of Materialsmentioning

confidence: 94%

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

et al. 2014

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“…5(a). The former is ascribed to the transverse acoustic (TA) mode and the latter to the nondegenerate longitudinal optical (LO) mode because of the presence of defects which is mainly due to the formation of oxygen vacancies [28][29][30]. The weak additional peaks present in the spectrum of disordered mixed phase CeO 2 cannot be assigned to any pure phase of CeO 2 which indicates that additional phases, possibly, may be due to additional bands of Ce 2 O 3 present in the sample (shown in circle in Fig.…”

Section: Raman Spectra Analysismentioning

confidence: 99%

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

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Samdarshi

Sreedhar

et al. 2015

Solar Energy Materials and Solar Cells

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“…[11][12][13][14][15][16][17][18][19] Since the luminescence approach typically used in literature is based on room -temperature measurements, limited excitation range, steady-state prevalence over time -resolved measurements, the correlation between the emission properties on one hand and the distribution and nature of Ln centers in CeO 2 on the other hand, could not be established. Therefore, fundamental questions -how are the defects distributed around Ln and what is the role of Ln ionic radius in determining the interactions between Ln and defects remained unanswered.…”

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confidence: 99%

Toward a Unified Description of Luminescence–Local Structure Correlation in Ln Doped CeO₂ Nanoparticles: Roles of Ln Ionic Radius, Ln Concentration, and Oxygen Vacancies

et al. 2015

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We propose a physical model for luminescence properties of trivalent lanthanide (Ln) doped into CeO 2 by use of low temperature, site selective, time-gated luminescence spectroscopy seconded by X-ray diffraction, Raman and Fourier transform infrared spectroscopy and transmission electron microscopy. The main findings can be summarized as follows: i) Ln situated to both left and right side to Gd in the Ln series, exhibit a two center distribution. Both Ln centers substitute for the tetravalent Ce fluorite sites being differentiated by the local symmetry: cubic, as a result of zero vacancy in the nearest-neighbor oxygen shell (cubic Ln center) and low symmetry, likely due to one vacancy in the nearest-neighbor oxygen shell (Ln -defect associate center); ii) A first example of Dy emission in an inversion (cubic) symmetry, characterized by strong lines at 679 and 764 nm is reported. This results is expected to challenge the way this lanthanide is currently used as a luminescence probe; iii) the relative contribution of the Ln centers to the overall emission depends on the Ln ionic radius: Sm exists predominantly as a cubic center while Er is found mostly as a vacancy associate; iv) Er, La codoped CeO 2 can be used as an effective model system to separate the effects of Ln concentration and subsequently induced oxygen vacancies on the efficiency of CeO 2 sensitization of Ln emission and v) Zr co -doping of CeO 2 obstructs the formation of Ln -defect associates. The implications of our findings for the interpretation of data already present in the literature are also discussed.

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Isolated centres versus defect associates in Sm³⁺-doped CeO₂: a spectroscopic investigation

Cited by 30 publications

References 38 publications

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

Toward a Unified Description of Luminescence–Local Structure Correlation in Ln Doped CeO₂ Nanoparticles: Roles of Ln Ionic Radius, Ln Concentration, and Oxygen Vacancies

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Isolated centres versus defect associates in Sm3+-doped CeO2: a spectroscopic investigation

Cited by 30 publications

References 38 publications

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

Structure and Oxide Ion Conductivity: Local Order, Defect Interactions and Grain Boundary Effects in Acceptor-Doped Ceria

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

Toward a Unified Description of Luminescence–Local Structure Correlation in Ln Doped CeO2 Nanoparticles: Roles of Ln Ionic Radius, Ln Concentration, and Oxygen Vacancies

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Isolated centres versus defect associates in Sm³⁺-doped CeO₂: a spectroscopic investigation

Toward a Unified Description of Luminescence–Local Structure Correlation in Ln Doped CeO₂ Nanoparticles: Roles of Ln Ionic Radius, Ln Concentration, and Oxygen Vacancies