An atomistic modelling investigation of the defect chemistry of SrTiO3 and its Ruddlesden-Popper phases, Srn+1TinO3n+1 (n = 1–3)

Wood, Nathan D; Teter, David M.; Tse, Joshua S.; Jackson, Robert A.; Cooke, David J.; Gillie, Lisa J.; Parker, Stephen C.; Molinari, Marco

doi:10.1016/j.jssc.2021.122523

Cited by 6 publications

(5 citation statements)

References 143 publications

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“…Such a linear correlation is expected from the observation that La is incorporated as a La 3+ ion on Sr 2+ sites. Thus, La can act as a donor leading to n-type semiconducting behavior in the films, which has also been discussed in ref . Simultaneously with increasing La concentration, we observe a significant decrease of the charge carrier mobility μ from ∼2.0 to ∼0.6 cm 2 V –1 s –1 (Figure b), which is attributed to enhanced scattering at an increased number of ionized impurities caused by the incorporation of La 3+ ions on Sr 2+ sites and/or a saturation effect. ,, As the resistivity is related to the charge carrier mobility μ and n by ρ = ne μ, it decreases continuously with increasing La concentration (Figure c).…”

Section: Resultssupporting

confidence: 79%

“…Our results indicate that the introduction of La in the gas phase under MOVPE conditions leads to the incorporation of La in the perovskite structure without a significant formation of a foreign phase and to n-type semiconducting electrical behavior. Several substitution schemes for La substitution in SrTiO 3 are described in ref . Due to the observed n-type conductivity of the films and the high oxygen partial pressure during deposition (see above), only the A-site substitution – La 3+ ions on Sr 2+ sites – is considered, which requires a charge compensation mechanism in order to achieve charge neutrality in the films.…”

Section: Resultsmentioning

confidence: 99%

“…19 Electronic compensation and n-type conductivity are provided by the substitution of La 3+ on Sr 2+ sites without the formation of Sr vacancies. 49,58,59 However, under the used deposition conditions (especially the high oxygen partial pressure), it is assumed that this only occurs at higher La concentrations in the gas phase, which might explain that more La ions are incorporated in the SrTiO 3 thin films than are electrically active and the lower charge carrier mobility observed in our MOVPE films compared to MBE films.…”

Section: ■ Experimental Sectionmentioning

confidence: 97%

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Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Baki

Abdeldayem

Morales

et al. 2023

Crystal Growth & Design

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La-doped SrTiO 3 thin films with high structural quality were homoepitaxially grown by the metal−organic vapor phase epitaxy (MOVPE) technique. Thermogravimetric characterization of the metal−organic precursors determines suitable flash evaporator temperatures for transferring the liquid source materials in the gas phase of the reactor chamber. An adjustment of the charge carrier concentration in the films, which is necessary for optimizing the thermoelectric power factor, was performed by introducing a defined amount of the metal−organic compound La(tmhd) 3 and tetraglyme to the liquid precursor solution. X-ray diffraction and atomic force microscopy verified the occurrence of the pure perovskite phase exhibiting a high structural quality for all La concentrations. The electrical conductivity of the films obtained from Hall-effect measurements increases linearly with the La concentration in the gas phase, which is attributed to the incorporation of La 3+ ions on the Sr 2+ perovskite sites by substitution inferred from photoemission spectroscopy. The resulting structural defects were discussed concerning the formation of occasional Ruddlesden−Popper-like defects. The thermoelectric properties determined by Seebeck measurements demonstrate the high potential of SrTiO 3 thin films grown by MOVPE for thermoelectric applications.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 97%

See 1 more Smart Citation

Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Baki

Abdeldayem

Morales

et al. 2023

Crystal Growth & Design

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“…The cut-off range was 10 Å. The Ir 3+ –O 2− pair potential was custom-fitted against DFT relaxed surface slabs of Ir doped SrTiO 3 (fitting details in the Supplementary Information ), and the other pair potentials used were the Teter Buckingham pair potentials (detailed in Table 1 ) 50 . An Ir 3+ ion was dragged through the region highlighted by the blue box in Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

Real-time insight into the multistage mechanism of nanoparticle exsolution from a perovskite host surface

et al. 2023

Self Cite

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In exsolution, nanoparticles form by emerging from oxide hosts by application of redox driving forces, leading to transformative advances in stability, activity, and efficiency over deposition techniques, and resulting in a wide range of new opportunities for catalytic, energy and net-zero-related technologies. However, the mechanism of exsolved nanoparticle nucleation and perovskite structural evolution, has, to date, remained unclear. Herein, we shed light on this elusive process by following in real time Ir nanoparticle emergence from a SrTiO3 host oxide lattice, using in situ high-resolution electron microscopy in combination with computational simulations and machine learning analytics. We show that nucleation occurs via atom clustering, in tandem with host evolution, revealing the participation of surface defects and host lattice restructuring in trapping Ir atoms to initiate nanoparticle formation and growth. These insights provide a theoretical platform and practical recommendations to further the development of highly functional and broadly applicable exsolvable materials.

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“…[64] The pair potentials used are the Teter Buckingham pair potential, which were derived specifically for solid state ionic materials. [65] These simulations were designed to investigate the impact of additional surface oxygen vacancies on the thermodynamic driving force behind the exsolution. The detailed simulation design and pair potentials parameters are included in the Supporting Information.…”

Section: Supporting Informationmentioning

confidence: 99%

Rapid Plasma Exsolution from an A‐site Deficient Perovskite Oxide at Room Temperature

Khalid

Alessi

et al. 2022

Advanced Energy Materials

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and catalysis, capable of producing supported nanoparticles in a single synthesis step. [2][3][4][5][6][7] Exsolution was first observed on stoichiometric perovskite oxides where nanoparticles could be produced from transition metals present on the B-site of the perovskite oxide. This mechanism was initially referred to as solid-state recrystallization or self-regeneration. [8] Recently, however, the use of defect chemistry to synthesize the host oxides has revived the interest in exsolution because it allows a greater number of active cations, enhanced surface nucleation and nanoparticle growth and an overall faster and better controlled process. [3,9,10] Furthermore, the defect chemistry also allows for a structure that does not change when the reaction conditions change from oxidizing to reducing thus producing extremely controllable and stable catalysts. These advances have triggered fast growing research activities in the exsolution of nanoparticles and their application for environmental catalysis, solid oxide fuel cells, electrolysers, and chemical looping. [11][12][13][14][15][16][17][18][19] Exsolution is now an established term that refers to the growth of nanoparticles via the supply of metallic ionic species from an oxide host. This allows the formation of well anchored and partially embedded nanoparticles (socketed) on the support oxide, while also exhibiting crystallographic alignment. The application interest in exsolved nanoparticles High-performance nanoparticle platforms can drive catalysis progress to new horizons, delivering environmental and energy targets. Nanoparticle exsolution offers unprecedented opportunities that are limited by current demanding process conditions. Unraveling new exsolution pathways, particularly at low-temperatures, represents an important milestone that will enable improved sustainable synthetic route, more control of catalysis microstructure as well as new application opportunities. Herein it is demonstrated that plasma direct exsolution at room temperature represents just such a step change in the synthesis. Moreover, the factors that most affect the exsolution process are identified. It is shown that the surface defects produced initiate exsolution under a brief ion bombardment of an argon low-pressure and lowtemperature plasma. This results in controlled nanoparticles with diameters ≈19-22 nm with very high number densities thus creating a highly active catalytic material for CO oxidation which rivals traditionally created exsolved samples.

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An atomistic modelling investigation of the defect chemistry of SrTiO3 and its Ruddlesden-Popper phases, Srn+1TinO3n+1 (n = 1–3)

Cited by 6 publications

References 143 publications

Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Real-time insight into the multistage mechanism of nanoparticle exsolution from a perovskite host surface

Rapid Plasma Exsolution from an A‐site Deficient Perovskite Oxide at Room Temperature

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An atomistic modelling investigation of the defect chemistry of SrTiO3 and its Ruddlesden-Popper phases, Srn+1TinO3n+1 (n = 1–3)

Cited by 6 publications

References 143 publications

Potential of La-Doped SrTiO3 Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Potential of La-Doped SrTiO3 Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Real-time insight into the multistage mechanism of nanoparticle exsolution from a perovskite host surface

Rapid Plasma Exsolution from an A‐site Deficient Perovskite Oxide at Room Temperature

Contact Info

Product

Resources

About

Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

Potential of La-Doped SrTiO₃ Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications