Structural Characterization and Photoluminescent Properties of (La1–xSmx)2Ti2O7 Solid Solutions Synthesized by a Sol–Gel Route

Shao, Z.; Saitzek, Sébastien; Blach, Jean‐François; Sayede, Adlane; Roussel, Pascal; Desfeux, Rachel

doi:10.1002/ejic.201100309

Cited by 35 publications

(17 citation statements)

References 49 publications

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“…Similar to Gd 2 Ti 2 O 7 , La 2 Ti 2 O 7 shows a decreasing intensity of the crystalline vibration mode together with the growth of a large asymmetric background signal as the fluence increases. Of particular interest are the prominent Raman bands found at $153 cm À1 , 240 cm À1 , and 343 cm À1 , which are most likely La-O bending modes [40]. Both Gd 2 Ti 2 O 7 and La 2 Ti 2 O 7 show a broad peak at around 800 cm À1 from the amorphous fraction, which suggests that the amorphous phases of the two materials are, indeed, quite similar i.e., their atomic arrangements at a full amorphous state are comparable.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

et al. 2015

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Swift heavy ion (2 GeV 181 Ta) irradiation-induced amorphization and temperature-induced recrystallization of cubic pyrochlore Gd 2 Ti 2 O 7 (Fd 3m) are compared with the response of a compositionally-similar material with a monoclinic-layered perovskite-type structure, La 2 Ti 2 O 7 (P2 1 ). The averaged electronic energy loss, dE/dx, was 37 keV/nm and 35 keV/nm in Gd 2 Ti 2 O 7 and La 2 Ti 2 O 7 , respectively. Systematic analysis of the structural modifications was completed using transmission electron microscopy, synchrotron X-ray diffraction, Raman spectroscopy, and small-angle X-ray scattering. Increasing ion-induced amorphization with increasing ion fluence was evident in the X-ray diffraction patterns of both compositions by a reduction in the intensity of the diffraction maxima concurrent with the growth in intensity of a broad diffuse scattering halo. Transmission electron microscopy analysis showed complete amorphization within ion tracks (diameter: $10 nm) for the perovskite-type material; whereas a concentric, core-shell morphology was evident in the ion tracks of the pyrochlore, with an outer shell of disordered yet still crystalline material with the fluorite structure surrounding an amorphous track core (diameter: $9 nm). The radiation response of both titanate oxides with the same stoichiometry can be understood in terms of differences in their structures and compositions. While the radiation damage susceptibility of pyrochlore A 2 B 2 O 7 materials decreases as a function of the cation radius ratio r A /r B , the current study correlates this behavior with the stability field of monoclinic structures, where r La /r Ti > r Gd /r Ti . Isochronal annealing experiments of the irradiated materials showed complete recrystallization of La 2 Ti 2 O 7 at 775°C and of Gd 2 Ti 2 O 7 at 850°C. The annealing behavior is discussed in terms of enhanced damage recovery in La 2 Ti 2 O 7 , compared to the pyrochlore compounds Gd 2 Ti 2 O 7 . The difference in the recrystallization behavior may be related to structural constraints, i.e., reconstructing a low symmetry versus a high symmetry phase.

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Section: Raman Spectroscopymentioning

confidence: 99%

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

et al. 2015

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“…The P s and T c of the high‐pressure phases of Sm 2 Ti 2 O 7 and Eu 2 Ti 2 O 7 were estimated to be about 2.1 μC/cm 2 and 1077°C, 2.7 μC/cm 2 and 1247°C, respectively . The photoluminescent properties of (Sm x La 1− x ) 2 Ti 2 O 7 powders prepared by sol–gel method were reported by Shao, et al…”

Section: Introductionmentioning

confidence: 80%

Crystallographic Structure and Ferroelectricity of (A_xLa_1−x)₂Ti₂O₇ (A = Sm and Eu) Solid Solutions with High T_c

et al. 2015

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The solubility and ferroelectric properties of (A x La 1x ) 2 Ti 2 O 7 (A = Sm and Eu) solid solutions were investigated. The crystallographic structure of the solid solutions was studied using X-ray diffraction and Raman spectroscopy. The solubility limits of Eu and Sm in (A x La 1x ) 2 Ti 2 O 7 were found to be greater than x = 0.5 and 0.8, respectively. The solid solutions had a monoclinic perovskite-like layered structure (PLS), similar to that of the pure La 2 Ti 2 O 7 , when x was less than the solubility limit. When x was above the solubility limit the materials were biphase. The biphases of (Sm x La 1x )Ti 2 O 7 (x = 0.9) consisted of (Sm x La 1x ) 2 Ti 2 O 7 with PLS and pure Sm 2 Ti 2 O 7 with pyrochlore structure, and the biphases of (Eu x La 1x )Ti 2 O 7 (x = 0.6, 0.7, and 0.8) consisted of (Eu x La 1x) 2 Ti 2 O 7 with PLS structure and La 3+ doped Eu 2 Ti 2 O 7 with pyrochlore structure. The effect of A-site substitution on the properties of La 2 Ti 2 O 7 was investigated by measuring the dielectric permittivity and loss at different frequencies and temperatures. The highest piezoelectric constant d 33 was 2.8 pC/N for (Sm 0.1 La 0.9 )Ti 2 O 7 . M. P. Paranthama-contributing editor Manuscript No. 36896.

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“…Attempts containing theoretical studies to address this issue include doping, 120,207,214,263,282,305,348,[372][373][374][375][376][377][378][379][380][381][382][383][384][385][386][387][388][389][390] forming oxynitrides and oxysulfide, 359,[391][392][393][394][395][396] introducing intrinsic defects, 100,145,146,[397][398][399] and forming solid-solutions. 249,258,259,400,401 Early studies mainly focused on doping cations in B site of ABO3 and derived complex perovskites. ACo1/3Nb2/3O3 (A = Ca, Sr, and Ba) with a random distribution of Co 2+ and Nb 5+ in M site in a manner of charge-balanced manner showed a visible light absorption band.…”

Section: Theoretical Modelling and Calculation Of Perovskite Photocatmentioning

confidence: 99%

Inorganic perovskite photocatalysts for solar energy utilization

et al. 2016

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The development and utilization of solar energy in environmental remediation and water splitting is being intensively studied worldwide. During the past few decades, tremendous efforts have been devoted to developing non-toxic, low-cost, efficient and stable photocatalysts for water splitting and environmental remediation. To date, several hundreds of photocatalysts mainly based on metal oxides, sulfides and (oxy)nitrides with different structures and compositions have been reported. Among them, perovskite oxides and their derivatives (layered perovskite oxides) comprise a large family of semiconductor photocatalysts because of their structural simplicity and flexibility. This review specifically focuses on the general background of perovskite and its related materials, summarizes the recent development of perovskite photocatalysts and their applications in water splitting and environmental remediation, discusses the theoretical modelling and calculation of perovskite photocatalysts and presents the key challenges and perspectives on the research of perovskite photocatalysts.

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Structural Characterization and Photoluminescent Properties of (La_1–xSm_x)₂Ti₂O₇ Solid Solutions Synthesized by a Sol–Gel Route

Cited by 35 publications

References 49 publications

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

Crystallographic Structure and Ferroelectricity of (A_xLa_1−x)₂Ti₂O₇ (A = Sm and Eu) Solid Solutions with High T_c

Inorganic perovskite photocatalysts for solar energy utilization

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Structural Characterization and Photoluminescent Properties of (La1–xSmx)2Ti2O7 Solid Solutions Synthesized by a Sol–Gel Route

Cited by 35 publications

References 49 publications

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

Response of Gd2Ti2O7 and La2Ti2O7 to swift-heavy ion irradiation and annealing

Crystallographic Structure and Ferroelectricity of (AxLa1−x)2Ti2O7 (A = Sm and Eu) Solid Solutions with High Tc

Inorganic perovskite photocatalysts for solar energy utilization

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Structural Characterization and Photoluminescent Properties of (La_1–xSm_x)₂Ti₂O₇ Solid Solutions Synthesized by a Sol–Gel Route

Crystallographic Structure and Ferroelectricity of (A_xLa_1−x)₂Ti₂O₇ (A = Sm and Eu) Solid Solutions with High T_c