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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Precisely modulate interfacial Bi-O bridge bond in Co-TCPP/Bi 3 O 4 Br to trigger long-lasting charge separation for boosting CO 2 photoreduction

Insufficient charge separation and feeble CO 2 activation limit the CO 2 photoreduction efficiency. It is highly desirable to consciously construct organic–inorganic hybrid composites to simultaneously accelerate charge separation and provide favorable active sites. Herein, a defect-induced interfacial Bi-O bridge bond is constructed by grafting terminal O of cobalt porphyrin (Co-TCPP) with Bi 3 O4Br. Systematic investigations reveal that the Bi-O bridge bond as the charge migration bridge accelerates the extraction and transfer of electron from the external [Bi 3 O 4 ] layers to Co-TCPP, and the millisecond separation lifetime of electrons on Co-TCPP can be achieved. Co atoms as the active sites optimized the CO 2 adsorption and activation, thus promoting the formation of COOH*. As a result, the CO 2 photoreduction rate of 0.5% Co-TCPP/Bi 3 O4Br reaches 71.3 μmol g -1 h -1 in pure water, 2.53-fold of that on the pristine Bi 3 O4Br. This work provides atomistic insights and strategies for the construction of new organic–inorganic hybrid materials for artificial photosynthesis and CO 2 photoreduction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A hybrid Monte Carlo study of bond-stretching electron–phonon interactions and charge order in BaBiO3

Abstract The relationship between electron–phonon ( e -ph) interactions and charge-density-wave (CDW) order in the bismuthate family of high-temperature superconductors remains unresolved. We address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO 3 . Our model includes the Bi 6 s and O 2 p σ orbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping integral. We simulate three-dimensional clusters of up to 4000 orbitals, with input model parameters taken from ab initio electronic structure calculations and a phonon energy ℏΩ 0 = 60 meV. Our results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system, despite a relatively small dimensionless coupling. We also find that the transition deviates from the weak-coupling Peierls’ picture. This work demonstrates that off-diagonal e -ph interactions in orbital space are vital in establishing the bismuthate phase diagram.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Lattice Effect on the Superexchange Interaction in Antiferromagnetic Bi 2.1 Sr 1.9 CaCu 2 O 8+δ

By employing Raman scattering and X-ray diffraction techniques on antiferromagnetic Bi 2.1 Sr 1.9 CaCu 2 O 8+δ within the same pressure conditions, we tracked the evolution of the two-magnon spectrum and structural parameters under pressures of up to nearly 30 GPa. Consequently, we established the relationship between pressure, in-plane lattice parameter d, and superexchange interaction J as J ~ d -(6.6±0.2 ). Within the examined pressure range, this compound did not exhibit superconductivity, as determined by a sensitive magnetic measurement technique. Additionally, we observed phonon anomalies, suggesting possible disorder effects in Bi-O layers and reduced charge transfer from these layers, particularly above 10 GPa. Finally, we discuss the impacts of pressure and chemical doping on J and the structure, along with their implications for superconductivity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Realization of Electron Antidoping by Modulating the Breathing Distortion in BaBiO 3

The recent proposal of antidoping scheme breaks new ground in conceiving conversely functional materials and devices; yet, the few available examples belong to the correlated electron systems. Here, we demonstrate both theoretically and experimentally that the main group oxide BaBiO 3 is a model system for antidoping using oxygen vacancies. The first-principles calculations show that the band gap systematically increases due to the strongly enhanced Bi-O breathing distortions away from the vacancies and the annihilation of Bi 6 s /O 2 p hybridized conduction bands near the vacancies. Our further spectroscopic experiments confirm that the band gap increases systematically with electron doping, with a maximal gap enhancement of ~75% when the film's stoichiometry is reduced to BaBiO 2.75 . These results unambiguously demonstrate the remarkable antidoping effect in a material without strong electron correlations and underscores the importance of bond disproportionation in realizing such an effect.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Unveiling the Degradation Mechanism of High-Temperature Superconductor Bi 2 Sr 2 CaCu 2 O 8+δ in Water-Bearing Environments

We report the physical properties of copper oxide high-temperature superconductors have been studied extensively, such as its band structure, and doping effects of Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212). However, some chemical-related properties of these superconductors are rarely reported, such as their stability in air. Here, we report experiments combined with ab initio calculations that address the effects of water in contact with Bi-2212. The evolution of Bi-2212 flake with exposure to water for different time intervals were tested and characterized by optical microscopy (OM), atomic force microscopy (AFM), Raman spectroscopy, transmission electron microscopy (TEM) and electrical measurements. The thickness of Bi-2212 flakes is gradually decreased in water, and some thin flakes can be completely etched away after a few days. The stability of Bi-2212 in other solvents is also evaluated, including alcohol, acetone, HCl and KOH. The morphology of Bi-2212 flakes is relatively stable in organic solvents. However, the flakes are etched relatively quick in HCl and KOH, especially in acidic environment. Our results imply that hydrogen ion is primarily responsible for the deterioration of their properties. Both TEM and calculation results demonstrate that the atoms in Bi-O plane is relatively stable when compared to the inner atoms in Sr-O, Ca-O and Cu-O planes. This work contributes towards understanding the chemical stability of Bi-2212 superconducting device in environmental medium, which is important for both fundamental studies and practical applications of copper oxide high-temperature superconductors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Observation of van der Waals phonons in the single-layer cuprate ( Bi , Pb ) 2 ( Sr , La ) 2 CuO 6 + δ

Interlayer van der Waals (vdW) coupling is generic in two-dimensional materials such as graphene and transition-metal dichalcogenides, which can induce very low-energy phonon modes. Using high-resolution inelastic hard x-ray scattering, we uncover the ultralow energy phonon mode along the Cu-O bond direction in the high- T c cuprate (Bi,Pb) 2 (Sr,La) 2 ⁢CuO 6+$\delta$ (Bi2201). The energy and full-width half-maximum (FWHM) of these modes are independent of temperature, while their intensity decreases with doping in accordance with an increasing c -axis lattice parameter. Here, we compare the experimental results to first-principles density functional theory simulations and identify the observed mode as a van der Waals phonon, which arises from the shear motion of the adjacent Bi-O layers. This shows that Bi-based cuprate has vibrational properties similar to graphene and transition-metal dichalcogenides, which can be exploited to engineer novel heterostructures.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the cubic Pn-3m space group. The structure is three-dimensional. Bi3+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Bi–O bond lengths are 2.42 Å. O2- is bonded to four equivalent Bi3+ atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 is Antimony trioxide-like structured and crystallizes in the tetragonal P-42_1c space group. The structure is three-dimensional. Bi3+ is bonded to five O2- atoms to form a mixture of distorted corner and edge-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.16–2.67 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Bi3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.18–2.81 Å. In the second Bi3+ site, Bi3+ is bonded to five O2- atoms to form a mixture of distorted corner and edge-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.17–2.60 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the third O2- site, O2- is bonded to four Bi3+ atoms to form corner-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiO2 by Materials Project

BiO2 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Bi is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Bi–O bond distances ranging from 2.18–2.66 Å. There are two inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Bi atoms. In the second O site, O is bonded to four equivalent Bi atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi4O7 by Materials Project

Bi4O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Bi+3.50+ sites. In the first Bi+3.50+ site, Bi+3.50+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with two equivalent BiO6 octahedra, corners with two equivalent BiO7 pentagonal bipyramids, and edges with two equivalent BiO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. There are four shorter (2.15 Å) and two longer (2.16 Å) Bi–O bond lengths. In the second Bi+3.50+ site, Bi+3.50+ is bonded to seven O2- atoms to form distorted BiO7 pentagonal bipyramids that share corners with two BiO6 octahedra, edges with two BiO6 octahedra, and edges with two equivalent BiO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–47°. There are a spread of Bi–O bond distances ranging from 2.27–2.72 Å. In the third Bi+3.50+ site, Bi+3.50+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with two equivalent BiO6 octahedra, corners with two equivalent BiO7 pentagonal bipyramids, and edges with two equivalent BiO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. There are a spread of Bi–O bond distances ranging from 2.12–2.18 Å. In the fourth Bi+3.50+ site, Bi+3.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.91 Å. In the fifth Bi+3.50+ site, Bi+3.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Bi–O bond distances ranging from 2.20–2.90 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to four Bi+3.50+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to four Bi+3.50+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to four Bi+3.50+ atoms. In the fourth O2- site, O2- is bonded to four Bi+3.50+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to four Bi+3.50+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to three Bi+3.50+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to four Bi+3.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiO2 by Materials Project

BiO2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Bi is bonded in a body-centered cubic geometry to eight equivalent O atoms. All Bi–O bond lengths are 2.39 Å. O is bonded to four equivalent Bi atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.19–2.58 Å. In the second Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.76 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Bi3+ atoms. In the third O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 is Antimony trioxide structured and crystallizes in the orthorhombic Pccn space group. The structure is three-dimensional. Bi3+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.13–2.58 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Bi3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to four equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiO2 by Materials Project

BiO2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Bi sites. In the first Bi site, Bi is bonded in a 4-coordinate geometry to four equivalent O atoms. There are two shorter (2.21 Å) and two longer (2.33 Å) Bi–O bond lengths. In the second Bi site, Bi is bonded to six O atoms to form corner-sharing BiO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Bi–O bond distances ranging from 2.12–2.19 Å. There are two inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to three Bi atoms. In the second O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent Bi atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.20–2.81 Å. In the second Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.35–2.56 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Bi3+ and one O2- atom. The O–O bond length is 1.52 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the cubic I23 space group. The structure is three-dimensional. Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.13–3.06 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to two equivalent Bi3+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2O3 by Materials Project

Bi2O3 crystallizes in the tetragonal P-4b2 space group. The structure is three-dimensional. Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.35–2.51 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the third O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fourth O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra.

36 MATERIALS SCIENCE↗