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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba10IBr4N5 by Materials Project

Ba10N5IBr4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to three N3-, one I1-, and two Br1- atoms to form a mixture of distorted corner and edge-sharing BaIBr2N3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Ba–N bond distances ranging from 2.81–2.86 Å. The Ba–I bond length is 3.56 Å. Both Ba–Br bond lengths are 3.53 Å. In the second Ba2+ site, Ba2+ is bonded to three N3-, one I1-, and two equivalent Br1- atoms to form a mixture of distorted corner and edge-sharing BaIBr2N3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are one shorter (2.81 Å) and two longer (2.86 Å) Ba–N bond lengths. The Ba–I bond length is 3.56 Å. There are one shorter (3.52 Å) and one longer (3.53 Å) Ba–Br bond lengths. In the third Ba2+ site, Ba2+ is bonded to three N3- and three Br1- atoms to form a mixture of distorted corner and edge-sharing BaBr3N3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.85 Å) and one longer (2.86 Å) Ba–N bond lengths. All Ba–Br bond lengths are 3.51 Å. In the fourth Ba2+ site, Ba2+ is bonded to three N3- and three Br1- atoms to form a mixture of distorted corner and edge-sharing BaBr3N3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Ba–N bond distances ranging from 2.84–2.86 Å. There are two shorter (3.51 Å) and one longer (3.52 Å) Ba–Br bond lengths. In the fifth Ba2+ site, Ba2+ is bonded to three N3-, one I1-, and two Br1- atoms to form a mixture of distorted corner and edge-sharing BaIBr2N3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are one shorter (2.82 Å) and two longer (2.85 Å) Ba–N bond lengths. The Ba–I bond length is 3.56 Å. There are one shorter (3.53 Å) and one longer (3.54 Å) Ba–Br bond lengths. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded to six Ba2+ atoms to form edge-sharing NBa6 octahedra. In the second N3- site, N3- is bonded to six Ba2+ atoms to form edge-sharing NBa6 octahedra. In the third N3- site, N3- is bonded to six Ba2+ atoms to form edge-sharing NBa6 octahedra. I1- is bonded in a 12-coordinate geometry to six Ba2+ atoms. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 6-coordinate geometry to six Ba2+ atoms. In the second Br1- site, Br1- is bonded in a 6-coordinate geometry to six Ba2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb3Br7N2O5 by Materials Project

Nb3O5Br7N2 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of eight ammonia molecules and two Nb3O5Br7 sheets oriented in the (1, 0, 0) direction. In each Nb3O5Br7 sheet, there are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to three O2- and three Br1- atoms. There are a spread of Nb–O bond distances ranging from 1.81–2.00 Å. There are a spread of Nb–Br bond distances ranging from 2.55–2.89 Å. In the second Nb5+ site, Nb5+ is bonded in a distorted octahedral geometry to four O2- and two equivalent Br1- atoms. There are two shorter (1.88 Å) and two longer (2.15 Å) Nb–O bond lengths. Both Nb–Br bond lengths are 2.56 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb5+ and one Br1- atom. The O–Br bond length is 3.62 Å. In the second O2- site, O2- is bonded in a linear geometry to two Nb5+ and one Br1- atom. The O–Br bond length is 3.16 Å. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ and two equivalent Br1- atoms. Both O–Br bond lengths are 2.96 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Nb5+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Nb5+ atom. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Nb5+ atom. In the fourth Br1- site, Br1- is bonded in a 8-coordinate geometry to two equivalent Nb5+ and six O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pa3Br by Materials Project

Pa3Br is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Pa sites. In the first Pa site, Pa is bonded to four equivalent Br atoms to form a mixture of distorted edge and corner-sharing PaBr4 cuboctahedra. All Pa–Br bond lengths are 3.19 Å. In the second Pa site, Pa is bonded in a distorted square co-planar geometry to four equivalent Br atoms. All Pa–Br bond lengths are 3.21 Å. Br is bonded to twelve Pa atoms to form a mixture of face, edge, and corner-sharing BrPa12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te6RuBr8 by Materials Project

RuTeTe5Br8 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ruthenium molecules, four tellurium molecules, and four Te5Br8 clusters. In each Te5Br8 cluster, there are five inequivalent Te1+ sites. In the first Te1+ site, Te1+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.16 Å. In the second Te1+ site, Te1+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.04 Å. In the third Te1+ site, Te1+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.59–3.05 Å. In the fourth Te1+ site, Te1+ is bonded in a distorted rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.56–3.34 Å. In the fifth Te1+ site, Te1+ is bonded in a T-shaped geometry to three Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.59–2.78 Å. There are eight inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the second Br1- site, Br1- is bonded in an L-shaped geometry to two Te1+ atoms. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the fourth Br1- site, Br1- is bonded in a distorted L-shaped geometry to two Te1+ atoms. In the fifth Br1- site, Br1- is bonded in a distorted single-bond geometry to two Te1+ atoms. In the sixth Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the seventh Br1- site, Br1- is bonded in a 2-coordinate geometry to two Te1+ atoms. In the eighth Br1- site, Br1- is bonded in a 2-coordinate geometry to two Te1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaH15C5Br3O5 by Materials Project

LaC5H15O5Br3 is Iron carbide-derived structured and crystallizes in the orthorhombic Pna2_1 space group. The structure is one-dimensional and consists of two LaC5H15O5Br3 ribbons oriented in the (0, 1, 0) direction. La3+ is bonded in a 5-coordinate geometry to five O2- and three Br1- atoms. There are a spread of La–O bond distances ranging from 2.31–2.44 Å. There are a spread of La–Br bond distances ranging from 3.08–3.28 Å. There are five inequivalent C1- sites. In the first C1- site, C1- is bonded in a tetrahedral geometry to three H1+ and one O2- atom. There is one shorter (1.10 Å) and two longer (1.11 Å) C–H bond length. The C–O bond length is 1.38 Å. In the second C1- site, C1- is bonded in a tetrahedral geometry to three H1+ and one O2- atom. All C–H bond lengths are 1.11 Å. The C–O bond length is 1.38 Å. In the third C1- site, C1- is bonded in a tetrahedral geometry to three H1+ and one O2- atom. All C–H bond lengths are 1.11 Å. The C–O bond length is 1.38 Å. In the fourth C1- site, C1- is bonded in a tetrahedral geometry to three H1+ and one O2- atom. There is two shorter (1.11 Å) and one longer (1.12 Å) C–H bond length. The C–O bond length is 1.37 Å. In the fifth C1- site, C1- is bonded in a tetrahedral geometry to three H1+ and one O2- atom. There are a spread of C–H bond distances ranging from 1.10–1.12 Å. The C–O bond length is 1.37 Å. There are fifteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one La3+ and one C1- atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one La3+, one C1-, and one Br1- atom. The O–Br bond length is 2.64 Å. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one La3+ and one C1- atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one La3+ and one C1- atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one La3+, one C1-, and one Br1- atom. The O–Br bond length is 2.74 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 1-coordinate geometry to one La3+ and one Br1- atom. The Br–Br bond length is 2.87 Å. In the second Br1- site, Br1- is bonded in a 1-coordinate geometry to one La3+, one O2-, and one Br1- atom. In the third Br1- site, Br1- is bonded in a 1-coordinate geometry to one La3+ and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbPdC4Br by Materials Project

RbPdC4Br crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a rectangular see-saw-like geometry to four equivalent Br1- atoms. All Rb–Br bond lengths are 3.72 Å. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded to four equivalent C+0.50- and two equivalent Br1- atoms to form corner-sharing PdC4Br2 octahedra. The corner-sharing octahedral tilt angles are 0°. All Pd–C bond lengths are 2.00 Å. Both Pd–Br bond lengths are 2.77 Å. In the second Pd2+ site, Pd2+ is bonded to four equivalent C+0.50- and two Br1- atoms to form corner-sharing PdC4Br2 octahedra. The corner-sharing octahedral tilt angles are 0°. All Pd–C bond lengths are 2.01 Å. Both Pd–Br bond lengths are 2.62 Å. There are two inequivalent C+0.50- sites. In the first C+0.50- site, C+0.50- is bonded in a linear geometry to one Pd2+ and one C+0.50- atom. The C–C bond length is 1.25 Å. In the second C+0.50- site, C+0.50- is bonded in a linear geometry to one Pd2+ and one C+0.50- atom. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded to four equivalent Rb1+ and two Pd2+ atoms to form a mixture of edge and corner-sharing BrRb4Pd2 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second Br1- site, Br1- is bonded to four equivalent Rb1+ and two Pd2+ atoms to form a mixture of edge and corner-sharing BrRb4Pd2 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. All Br–Rb bond lengths are 3.72 Å. The Br–Pd bond length is 2.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Influence of Methylammonium Chloride on Wide-Bandgap Halide Perovskites Films for Solar Cells

Wide-bandgap perovskites are of paramount importance as the photoactive layer of the top cell in high-efficiency tandem solar cells. Comparably high Br contents are required to widen the perovskite bandgap. However, the increase in Br content causes heterogeneous halide distribution and photoinstability. Here, in this study, the positive effect of the additive methylammonium chloride (MACl) on the optical and electronic properties of Br-rich perovskite, deposited using N-methyl-2-pyrrolidone (NMP) as co-solvent and the gas quenching method, is investigated. Simultaneous in situ grazing-incidence wide-angle X-ray scattering and photoluminescence spectroscopy are used to track the evolution of the structural and optoelectronic properties of the perovskites with different amounts of Br and MACl during the spin-coating and thermal annealing steps. The formation mechanism is elucidated in the presence of MACl. It is observed that chloride ions inhibit the intermediate phases, favoring the formation of a perovskite phase with higher crystallinity. Nano X-ray fluorescence mapping recognizes Br-richer and poorer nanometric domains, whose average sizes reduce for samples with MACl. In conclusion, it is demonstrated that adding MACl affects the formation of wide-bandgap perovskites via destabilization of the intermediate phases and acts on the homogenization of the halide distribution, leading to improved solar cell performances.

14 SOLAR ENERGY↗
DOE OSTI2021

Texture Formation in Polycrystalline Thin Films of All‐Inorganic Lead Halide Perovskite

Abstract Controlling grain orientations within polycrystalline all‐inorganic halide perovskite solar cells can help increase conversion efficiencies toward their thermodynamic limits; however, the forces governing texture formation are ambiguous. Using synchrotron X‐ray diffraction, mesostructure formation within polycrystalline CsPbI 2.85 Br 0.15 powders as they cool from a high‐temperature cubic perovskite (α‐phase) is reported. Tetragonal distortions (β‐phase) trigger preferential crystallographic alignment within polycrystalline ensembles, a feature that is suggested here to be coordinated across multiple neighboring grains via interfacial forces that select for certain lattice distortions over others. External anisotropy is then imposed on polycrystalline thin films of orthorhombic (γ‐phase) CsPbI 3‐ x Br x perovskite via substrate clamping, revealing two fundamental uniaxial texture formations; i) I‐rich films possess orthorhombic‐like texture (<100> out‐of‐plane; <010> and <001> in‐plane), while ii) Br‐rich films form tetragonal‐like texture (<110> out‐of‐plane; <110> and <001> in‐plane). In contrast to relatively uninfluential factors like the choice of substrate, film thickness, and annealing temperature, Br incorporation modifies the γ‐CsPbI 3− x Br x crystal structure by reducing the orthorhombic lattice distortion (making it more tetragonal‐like) and governs the formation of the different, energetically favored textures within polycrystalline thin films.

Steele, Julian A.↗
DOE OSTI2020

Structural Diversity and Magnetic Properties of Hybrid Ruthenium Halide Perovskites and Related Compounds

Abstract There has been a great deal of recent interest in extended compounds containing Ru 3+ and Ru 4+ in light of their range of unusual physical properties. Many of these properties are displayed in compounds with the perovskite and related structures. Here we report an array of structurally diverse hybrid ruthenium halide perovskites and related compounds: MA 2 Ru X 6 ( X =Cl or Br), MA 2 M RuX 6 ( M =Na, K or Ag; X =Cl or Br) and MA 3 Ru 2 X 9 ( X =Br) based upon the use of methylammonium (MA=CH 3 NH 3 + ) on the perovskite A site. The compounds MA 2 Ru X 6 with Ru 4+ crystallize in the trigonal space group and can be described as vacancy‐ordered double‐perovskites. The ordered compounds MA 2 M Ru X 6 with M + and Ru 3+ crystallize in a structure related to BaNiO 3 with alternating MX 6 and Ru X 6 face‐shared octahedra forming linear chains in the trigonal space group. The compound MA 3 Ru 2 Br 9 crystallizes in the orthorhombic Cmcm space group and displays pairs of face‐sharing octahedra forming isolated Ru 2 Br 9 moieties with very short Ru–Ru contacts of 2.789 Å. The structural details, including the role of hydrogen bonding and dimensionality, as well as the optical and magnetic properties of these compounds are described. The magnetic behavior of all three classes of compounds is influenced by spin–orbit coupling and their temperature‐dependent behavior has been compared with the predictions of the appropriate Kotani models.

Vishnoi, Pratap↗
DOE OSTI2020

Structural Diversity and Magnetic Properties of Hybrid Ruthenium Halide Perovskites and Related Compounds

There has been a great deal of recent interest in extended compounds containing Ru 3+ and Ru 4+ in light of their range of unusual physical properties. Many of these properties are displayed in compounds with the perovskite and related structures. Here we report an array of structurally diverse hybrid ruthenium halide perovskites and related compounds: MA 2 RuX 6 (X=Cl or Br), MA 2 MRuX 6 (M=Na, K or Ag; X=Cl or Br) and MA 3 Ru 2 X 9 (X=Br) based upon the use of methylammonium (MA=CH 3 NH 3 + ) on the perovskite A site. The compounds MA 2 RuX 6 with Ru 4+ crystallize in the trigonal space group R3¯m and can be described as vacancy-ordered double-perovskites. The ordered compounds MA 2 MRuX 6 with M + and Ru 3+ crystallize in a structure related to BaNiO 3 with alternating MX 6 and RuX 6 face-shared octahedra forming linear chains in the trigonal P3¯m space group. The compound MA 3 Ru 2 Br 9 crystallizes in the orthorhombic Cmcm space group and displays pairs of face-sharing octahedra forming isolated Ru 2 Br 9 moieties with very short Ru–Ru contacts of 2.789 Å. The structural details, including the role of hydrogen bonding and dimensionality, as well as the optical and magnetic properties of these compounds are described. The magnetic behavior of all three classes of compounds is influenced by spin–orbit coupling and their temperature-dependent behavior has been compared with the predictions of the appropriate Kotani models.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Three exceptions to the Grossman-Nir bound

A bstract We show that the Grossman-Nir (GN) bound, Br( K L → $$ {\pi}^0\nu \overline{\nu} $$ π 0 ν ν ¯ ) ≤ 4 . 3 Br( K + → $$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ ), can be violated in the presence of light new physics with flavor violating couplings. We construct three sample models in which the GN bound can be violated by orders of magnitude, while satisfying all other experimental bounds. In the three models the enhanced branching ratio Br( K L → π 0 + inv) is due to K L → π 0 Φ 1, K L → π 0 Φ 1 Φ 1 , K L → $$ {\pi}^0{\psi}_1{\overline{\psi}}_1 $$ π 0 ψ 1 ψ ¯ 1 transitions, respectively, where Φ 1 ( ψ 1 ) is a light scalar (fermion) that escapes the detector. In the three models Br( K + → π + + inv) remains very close to the SM value, while Br( K L → π 0 + inv) can saturate the present KOTO bound. Besides invisible particles in the final state (which may account for dark matter) the models require additional light mediators around the GeV-scale.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

LaBr 3 : Ce self-activation analysis for measuring fast neutron fields

Measurement of the fast neutron production rate in deuterium–tritium (D–T) fusion reactions is important for applications such as active interrogation, fusion diagnostics, and borehole logging. Such measurements are typically performed by neutron activation analysis of metal foils, especially copper. Copper foil activation analysis requires efficiency and energy calibrations of the detector used to measure the foil, and it relies on the detection of 511 keV gamma rays, which are prominent in the active background when neutrons are being produced. Alternatives, such as 79m Br produced by inelastic neutron scattering on 79 Br, are limited by short half-life, low-energy gamma emission, and inability to selectively measure D–T neutrons. This work describes a novel alternative approach to measure ≳10 MeV neutron fields based on self-activation analysis of a LaBr 3 :Ce detector. The activity of 78 Br, the activation product of the 79 Br(n,2n) 78 Br reaction, is used to determine the neutron flux and infer the neutron production rate. We experimentally demonstrate the method with a cylindrical LaBr 3 :Ce crystal with a diameter and height of 3.81 cm that was placed at an ~18 cm distance from the neutron production point, at a 90° angle with respect to the deuteron beam in a D–T neutron generator. Operating voltage and current of the generator were adjusted to evaluate the technique’s performance over a nominal generator output range of approximately (1 - 9) x 10 7 n/s. The neutron output obtained from LaBr 3 :Ce activation agrees to within three standard deviations of the output obtained using copper activation. The self-activation technique can be conveniently employed in a variety of applications to simplify measurements of fast neutrons produced in D–T fusion reactions.

Active interrogationLaBr3↗
DOE OSTI2025

Data-Driven Mapping of the Cesium Cadmium Bromide Phase Space Utilizing a Soft-Chemistry Approach

Soft-chemistry techniques provide a versatile approach to synthesizing inorganic materials under mild conditions, enabling access to compositions and structures that are challenging to achieve through traditional thermodynamically driven solid-state methods. However, these solution-based routes often result in phase competition, requiring precise control over reaction conditions to achieve selective product formation. While one-variable-at-a-time (OVAT) approaches have traditionally been used for phase selection, data-driven strategies are emerging as more efficient methods for navigating complex synthetic spaces. Ternary metal halides, such as cesium cadmium bromides (Cs–Cd–Br), are of growing interest due to their potential in wide and ultrawide band gap applications. Unlike the well-studied cesium lead halide phases, the compositional diversity and solution-based synthesis of ternary Cs–Cd–Br phases remain largely unexplored. This study systematically investigates the synthetic phase space of the Cs–Cd–Br system by constructing a data-driven phase map. Using a common set of precursors and a standardized experimental procedure, we successfully synthesize all four known Cs–Cd–Br phases—CsCdBr 3 , Cs 2 CdBr 4 , Cs 3 CdBr 5 , and Cs 7 Cd 3 Br 13 —each exhibiting distinct structures, morphologies, and optical properties. Our findings highlight the potential of soft-chemistry methods for expanding the library of ternary metal halides and provide key insights into the thermodynamic and kinetic factors governing phase formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Boosting the Oxygen Evolution Reaction by Tuning the Interfacial Iron Adsorption on Layered Double Hydroxide

Understanding the interaction between ions in the electrolyte and electrode materials plays an important role in optimizing the water electrolysis performance for hydrogen production. Herein, the synergistic effect of iron (Fe) in the electrolyte and interlayer anions within the layered structure on the oxygen evolution reaction (OER) has been investigated by combining material synthesis with controlled structure, multiple characterization techniques, and first-principles calculations. Nickel aluminum layered double hydroxides (NiAl-LDHs) with different interlayer anions (CO 3 2– , Cl – , and Br – ) show similar oxygen evolution activity in the absence of Fe species in the electrolyte. The addition of Fe into the electrolyte results in improved performance for all of the NiAl-LDHs, following the rank LDH-Br > LDH-Cl > LDH-CO 3 , under all of the conditions with varied concentration of Fe. X-ray absorption spectroscopy and identical location electron microscopy analyses show that the LDH structure remains unchanged after the OER activity test, while in situ stationary probe rotating disk electrode inductively coupled plasma mass spectrometry (SPRDE-ICP-MS) measurements show partial dissolution of the intercalating halide ions during cycling, with less dissolution for Br-intercalated materials. Insights from theoretical calculations demonstrate the thermodynamic preference of Br – to remain intercalated in the presence of Fe, while the stronger adsorption of Fe(OH) 3 species on the LDH-Br sample promotes the OER activity. In conclusion, these results provide mechanistic insights into the rational design of active layered materials with an enhanced OER performance for efficient water electrolysis.

58 GEOSCIENCES↗
DOE OSTI2022

Harvesting krypton isotopes from the off-gas of an irradiated water target to generate 76Br and 77Br

Abstract A flowing-water target was irradiated with a 150 MeV/nucleon beam of 78 Kr at the National Superconducting Cyclotron Laboratory to produce 77 Kr and 76 Kr. Real-time gamma-imaging measurements revealed the mass transport of the krypton radioisotopes through the target-water processing, or “isotope harvesting”, system. The production rates were determined to be 2.7(1) × 10 –4 nuclei of 76 Kr and 1.18(6) × 10 –2 nuclei of 77 Kr formed per incident 78 Kr ion. Utilizing an off-gas processing line as part of the isotope harvesting system, a total of 7.2(1) MBq of 76 Kr and 19.1(6) MBq of 77 Kr were collected in cold traps. Through the decay, the daughter radionuclides 76 Br and 77 Br were generated and removed from the traps with an average efficiency of 77 ± 12%. Due to the differences in half-lives of 76 Kr and 77 Kr, it was possible to isolate a pure sample of 76 Br with 99.9% radionuclidic purity. The successful collection of krypton radioisotopes to generate 76 Br and 77 Br demonstrates the feasibility of gas-phase isotope harvesting from irradiated accelerator cooling-water. Larger-scale collections are planned for collecting by-product radionuclides from the Facility for Rare Isotope Beams.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

Broadband light emitting zero-dimensional antimony and bismuth-based hybrid halides with diverse structures

Low-dimensional organic–inorganic metal halides have recently attracted extensive attention because of their various structures and distinguished photoelectric properties. Herein, we report a series of new zero-dimensional organic–inorganic hybrid metal halides: (TMEDA) 3 Bi 2 Cl 12 ·H 2 O, (TMEDA) 3 Bi 2 Br 12 ·H 2 O, (TMEDA) 3 Sb 2 Br 12 ·H 2 O, and (TMEDA) 5 Sb 6 Cl 28 ·2H 2 O [TMEDA = N,N,N'·trimethylethylenediamine]. (TMEDA) 3 M 2 X 12 ·H 2 O (M = Bi or Sb, X = Cl or Br) crystallizes in the monoclinic space group P2 1 /n, and (TMEDA) 5 Sb 6 Cl 28 ·2H 2 O crystallizes in the orthorhombic space group Pnma. (TMEDA) 3 M 2 X 12 possesses a zero-dimensional structure with the metal halide ions of [MBr 6 ] 3- isolated by the organic TMEDA 2+ cations. Interestingly, the (TMEDA) 5 Sb 6 Cl 28 ·2H 2 O structure consists of a combination of corner-connected octahedra [Sb 4 Cl 18 ] 6- and edge-shared [Sb 2 Cl 10 ] 4- , which is quite rare. The light emission of all these compounds was measured, and (TMEDA) 3 Sb 2 Br 12 ·H 2 O exhibits the most intense luminescence. Upon 400 nm ultraviolet light excitation, (TMEDA) 3 Sb 2 Br 12 ·H 2 O exhibited strong broadband yellow emission centered at 625 nm with a full-width at half-maximum of ~150 nm originating from self-trapped excitons. In conclusion, this work suggests the possibility of new types of hybrid halides by introducing different metal centers and probing the structural evolution and photoluminescent properties, serving as a reference for the relationship between structure and luminescent performance and demonstrating their potential use as phosphors in light-emitting diodes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Production of Radiohalogens: Bromine and Astatine for Imaging and Therapy

Over the course of this two year grant, we have developed and optimized new methods for the production of clinical quality 76 Br, 77 Br, and 80m Br at the University of Wisconsin. This includes the synthesis of a novel isotopically enriched cobalt-selenium intermetallic compound, its fabrication into robust cyclotron targets, and the chemical isolation of the resulting bromine radionuclide. Compared with the previous state-of-the-art, these methods demonstrate a six-times larger 76 Br and three-times larger 77 Br production capacity for a 3-hour cyclotron irradiation. Additionally, the cyclotron targets are exceptionally robust to this process, allowing for their reuse for dozens of radiobromine productions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Impact of Boron-Containing Lubricant Additive on Three-Way Catalyst Reactivity and Physicochemical Properties

Boron-containing compounds are one of the lubricant additive options due to their suitable properties for additives and have been used as commercial lubricant additives. In the present study, the impact of a boron-containing lubricant oil additive, AR9100 (BR), on Pd/Rh-based three-way catalyst (TWC) performance is investigated, and the results are compared with the baseline no-additive (NA) case and the industry standard zinc dialkyl-dithiophosphate (ZDDP) results. Accelerated engine aging is performed using a genset to expose the catalysts to lubricant additives at high temperatures. All aged TWC samples are investigated for reactivity in a bench-flow reactor and characterized using a variety of analytical techniques. Compared with the no-additive case, the temperatures of 90% conversion (T 90 ) of NO, CO, C 3 H 6 , and C 3 H 8 for the ZDDP-aged TWC sample increased by 34, 30, 37, and 48 °C. However, the T 90 of all gas species for the BR-aged TWC sample are similar to the NA-aged TWC sample. Additionally, a significant decrease in water–gas shift reactivity and oxygen storage capacity is observed in the ZDDP-aged sample, but not in the BR-aged sample. Inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis and electron probe microanalysis (EPMA) maps of accelerated engine aging samples show the presence of phosphorus and boron in ZDDP- and BR-aged TWC samples, respectively. However, no boron-related peaks are observed in the X-ray diffraction (XRD) pattern of the BR-aged TWC sample, which may exist in the form of an amorphous phase.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗