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DOE OSTI2020

Materials Data on Hg11I2BrClO4 by Materials Project

Hg11O4I2BrCl crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eleven inequivalent Hg+1.09+ sites. In the first Hg+1.09+ site, Hg+1.09+ is bonded in a distorted L-shaped geometry to two O2-, two I1-, and one Br1- atom. There are one shorter (2.22 Å) and one longer (2.77 Å) Hg–O bond lengths. There are one shorter (3.55 Å) and one longer (3.79 Å) Hg–I bond lengths. The Hg–Br bond length is 3.48 Å. In the second Hg+1.09+ site, Hg+1.09+ is bonded in a distorted L-shaped geometry to two O2-, two I1-, and one Cl1- atom. There are one shorter (2.21 Å) and one longer (2.76 Å) Hg–O bond lengths. There are one shorter (3.57 Å) and one longer (3.78 Å) Hg–I bond lengths. The Hg–Cl bond length is 3.44 Å. In the third Hg+1.09+ site, Hg+1.09+ is bonded in a distorted single-bond geometry to one O2-, one I1-, and one Br1- atom. The Hg–O bond length is 2.19 Å. The Hg–I bond length is 3.33 Å. The Hg–Br bond length is 3.07 Å. In the fourth Hg+1.09+ site, Hg+1.09+ is bonded in a distorted single-bond geometry to one O2-, one I1-, and one Cl1- atom. The Hg–O bond length is 2.18 Å. The Hg–I bond length is 3.37 Å. The Hg–Cl bond length is 2.98 Å. In the fifth Hg+1.09+ site, Hg+1.09+ is bonded in a distorted L-shaped geometry to two O2-, one Br1-, and one Cl1- atom. There are one shorter (2.23 Å) and one longer (2.61 Å) Hg–O bond lengths. The Hg–Br bond length is 3.68 Å. The Hg–Cl bond length is 3.21 Å. In the sixth Hg+1.09+ site, Hg+1.09+ is bonded in a distorted L-shaped geometry to two O2- and one Br1- atom. There are one shorter (2.23 Å) and one longer (2.62 Å) Hg–O bond lengths. The Hg–Br bond length is 3.30 Å. In the seventh Hg+1.09+ site, Hg+1.09+ is bonded in a linear geometry to two O2-, two I1-, and one Br1- atom. Both Hg–O bond lengths are 2.08 Å. There are one shorter (3.34 Å) and one longer (3.35 Å) Hg–I bond lengths. The Hg–Br bond length is 3.66 Å. In the eighth Hg+1.09+ site, Hg+1.09+ is bonded in a distorted single-bond geometry to one O2-, one Br1-, and one Cl1- atom. The Hg–O bond length is 2.18 Å. The Hg–Br bond length is 3.61 Å. The Hg–Cl bond length is 3.09 Å. In the ninth Hg+1.09+ site, Hg+1.09+ is bonded in a distorted single-bond geometry to one O2- and one Br1- atom. The Hg–O bond length is 2.20 Å. The Hg–Br bond length is 3.14 Å. In the tenth Hg+1.09+ site, Hg+1.09+ is bonded in a single-bond geometry to one O2-, three I1-, and one Cl1- atom. The Hg–O bond length is 2.22 Å. There are a spread of Hg–I bond distances ranging from 3.44–3.59 Å. The Hg–Cl bond length is 3.41 Å. In the eleventh Hg+1.09+ site, Hg+1.09+ is bonded in a single-bond geometry to one O2-, three I1-, and one Br1- atom. The Hg–O bond length is 2.22 Å. There are a spread of Hg–I bond distances ranging from 3.44–3.57 Å. The Hg–Br bond length is 3.40 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hg+1.09+ atoms to form distorted edge-sharing OHg4 tetrahedra. In the second O2- site, O2- is bonded to four Hg+1.09+ and one Br1- atom to form distorted edge-sharing OHg4Br tetrahedra. The O–Br bond length is 3.36 Å. In the third O2- site, O2- is bonded to four Hg+1.09+ and one I1- atom to form a mixture of distorted edge and corner-sharing OHg4I tetrahedra. The O–I bond length is 3.56 Å. In the fourth O2- site, O2- is bonded to four Hg+1.09+ and one I1- atom to form a mixture of distorted edge and corner-sharing OHg4I tetrahedra. The O–I bond length is 3.57 Å. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a 8-coordinate geometry to seven Hg+1.09+ and one O2- atom. In the second I1- site, I1- is bonded in a 6-coordinate geometry to seven Hg+1.09+ and one O2- atom. Br1- is bonded in a 2-coordinate geometry to eight Hg+1.09+ and one O2- atom. Cl1- is bonded in a 2-coordinate geometry to five Hg+1.09+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(N3Cl)2 by Materials Project

Cu(N3Cl)2 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. Cu2+ is bonded in an octahedral geometry to six N atoms. There are a spread of Cu–N bond distances ranging from 1.87–1.93 Å. There are five inequivalent N sites. In the first N site, N is bonded in a single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. There are three shorter (2.71 Å) and one longer (2.72 Å) N–Cl bond lengths. In the second N site, N is bonded in a single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. All N–Cl bond lengths are 2.70 Å. In the third N site, N is bonded in a single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. All N–Cl bond lengths are 2.70 Å. In the fourth N site, N is bonded in a single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. All N–Cl bond lengths are 2.98 Å. In the fifth N site, N is bonded in a single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. All N–Cl bond lengths are 2.98 Å. Cl1- is bonded in a 8-coordinate geometry to twelve N atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sb2Te3H2C(NCl9)2 by Materials Project

CH2Cl2Sb2Te3(NCl8)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four dichloromethane molecules and four Sb2Te3(NCl8)2 clusters. In each Sb2Te3(NCl8)2 cluster, there are two inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded in an octahedral geometry to one N3- and five Cl1- atoms. The Sb–N bond length is 2.10 Å. There are a spread of Sb–Cl bond distances ranging from 2.37–2.47 Å. In the second Sb3+ site, Sb3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Sb–Cl bond distances ranging from 2.38–2.46 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted trigonal planar geometry to three Te4+ atoms. There are a spread of N–Te bond distances ranging from 2.01–2.07 Å. In the second N3- site, N3- is bonded in a trigonal planar geometry to one Sb3+ and two Te4+ atoms. Both N–Te bond lengths are 2.01 Å. There are three inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 4-coordinate geometry to one N3- and three Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.34–2.53 Å. In the second Te4+ site, Te4+ is bonded in a 6-coordinate geometry to two N3- and four Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.35–3.24 Å. In the third Te4+ site, Te4+ is bonded in a 6-coordinate geometry to two N3- and four Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.35–3.16 Å. There are sixteen inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the second Cl1- site, Cl1- is bonded in a 1-coordinate geometry to two Te4+ atoms. In the third Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to two Te4+ atoms. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the fifth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the seventh Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Sb3+ and one Te4+ atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the ninth Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one Sb3+ and one Te4+ atom. In the tenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the eleventh Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the twelfth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the thirteenth Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Sb3+ and one Te4+ atom. In the fourteenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the fifteenth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Sb3+ and one Te4+ atom. In the sixteenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2ClO3 by Materials Project

Cd2O3Cl crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Cd sites. In the first Cd site, Cd is bonded to five O and one Cl atom to form distorted edge-sharing CdClO5 octahedra. There are a spread of Cd–O bond distances ranging from 2.26–2.30 Å. The Cd–Cl bond length is 2.60 Å. In the second Cd site, Cd is bonded to four O and two equivalent Cl atoms to form distorted edge-sharing CdCl2O4 octahedra. There are two shorter (2.20 Å) and two longer (2.21 Å) Cd–O bond lengths. Both Cd–Cl bond lengths are 2.86 Å. There are two inequivalent O sites. In the first O site, O is bonded in a trigonal non-coplanar geometry to three Cd atoms. In the second O site, O is bonded in a trigonal non-coplanar geometry to three Cd atoms. Cl is bonded in a 3-coordinate geometry to three Cd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb3SmCl6 by Materials Project

Rb3SmCl6 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are a spread of Rb–Cl bond distances ranging from 3.52–3.89 Å. In the second Rb1+ site, Rb1+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are a spread of Rb–Cl bond distances ranging from 3.25–3.76 Å. In the third Rb1+ site, Rb1+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are a spread of Rb–Cl bond distances ranging from 3.30–3.79 Å. There are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Sm–Cl bond distances ranging from 2.68–2.73 Å. In the second Sm3+ site, Sm3+ is bonded in an octahedral geometry to six Cl1- atoms. There are two shorter (2.70 Å) and four longer (2.73 Å) Sm–Cl bond lengths. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Rb1+ and one Sm3+ atom. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Rb1+ and one Sm3+ atom. In the third Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Rb1+ and one Sm3+ atom. In the fourth Cl1- site, Cl1- is bonded to four Rb1+ and one Sm3+ atom to form distorted face-sharing ClRb4Sm square pyramids. In the fifth Cl1- site, Cl1- is bonded in a 1-coordinate geometry to four Rb1+ and one Sm3+ atom. In the sixth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Rb1+ and one Sm3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ni3Cl4 by Materials Project

Ni3Cl4 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Ni+1.33+ sites. In the first Ni+1.33+ site, Ni+1.33+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing NiCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Ni–Cl bond distances ranging from 2.44–2.49 Å. In the second Ni+1.33+ site, Ni+1.33+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing NiCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Ni–Cl bond distances ranging from 2.44–2.50 Å. In the third Ni+1.33+ site, Ni+1.33+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing NiCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Ni–Cl bond distances ranging from 2.44–2.50 Å. In the fourth Ni+1.33+ site, Ni+1.33+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing NiCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Ni–Cl bond distances ranging from 2.43–2.50 Å. In the fifth Ni+1.33+ site, Ni+1.33+ is bonded to six Cl1- atoms to form edge-sharing NiCl6 octahedra. There are a spread of Ni–Cl bond distances ranging from 2.41–2.44 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a rectangular see-saw-like geometry to four Ni+1.33+ atoms. In the second Cl1- site, Cl1- is bonded in a rectangular see-saw-like geometry to four Ni+1.33+ atoms. In the third Cl1- site, Cl1- is bonded in a rectangular see-saw-like geometry to four Ni+1.33+ atoms. In the fourth Cl1- site, Cl1- is bonded in a rectangular see-saw-like geometry to four Ni+1.33+ atoms. In the fifth Cl1- site, Cl1- is bonded to five Ni+1.33+ atoms to form a mixture of corner and edge-sharing ClNi5 square pyramids. In the sixth Cl1- site, Cl1- is bonded to five Ni+1.33+ atoms to form a mixture of corner and edge-sharing ClNi5 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2024

High‐Performance Ternary Organic Solar Cells with Enhanced Luminescence Efficiency and Miscibility Enabled by Two Compatible Acceptors

Abstract The ternary strategy has proven to be an effective method for improving the efficiency of organic solar cells (OSCs). However, designing and selecting the third component still pose challenges. In this study, this issue is addressed by focusing on the PBDB‐T:Y18‐F binary system and introducing a new, strong luminescent, asymmetric small‐molecule acceptor (SMA) called L8‐CBIC‐Cl, which shares a similar skeleton with Y18‐F. The similarity in molecular framework facilitates good compatibility between the two acceptors, resulting in the formation of an alloy‐like acceptor phase. Furthermore, the norbornenyl‐modified end group in L8‐CBIC‐Cl contributes to its strong luminescent properties, which in turn leads to a low non‐radiative energy loss and a high open‐circuit voltage. Consequently, the PBDB‐T:L8‐CBIC‐Cl:Y18‐F based ternary devices realize a high power conversion efficiency (PCE) up to 17.01%, which is higher than PBDB‐T:Y18‐F device (14.49%). Importantly, L8‐CBIC‐Cl exhibits a good universality as a guest acceptor in other three binary systems (D18:Y6, D18:BTP‐eC9‐4F, and D18:L8‐BO). The D18:L8‐BO:L8‐CBIC‐Cl device shows an impressive efficiency of 19%. The work demonstrates that employing SMA with a high PLQY and better miscibility with host acceptor as the third component has a great potential for developing high‐efficiency ternary OSCs.

Chemistry↗
DOE OSTI2021

Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear Pt II →Ge IV Complex

Abstract Searching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [( o ‐(Ph 2 P)C 6 H 4 ) 2 Ge IV Cl 2 ]Pt II Cl 2 and [( o ‐(Ph 2 P)C 6 H 4 ) 2 ClGe III ]Pt III Cl 3 , two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [( o ‐(Ph 2 P)C 6 H 4 ) 2 ClGe III ]Pt I Cl with quantum yields of 1.7 % and 3.2 % for the Ge IV –Pt II and Ge III –Pt III isomers, respectively. Conversion of the Ge IV –Pt II isomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the Ge III –Pt III isomer point to a ligand arene–Cl . charge‐transfer complex as an intermediate.

Karimi, Mohammadjavad↗
DOE OSTI2021

Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear Pt II →Ge IV Complex

Searching for a connection between the two-electron redox behavior of Group-14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(o-(Ph 2 P)C 6 H 4 ) 2 Ge IV Cl 2 ]Pt II Cl 2 and [(o-(Ph 2 P)C 6 H 4 ) 2 ClGe III ]Pt III Cl 3 , two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o-(Ph 2 P)C 6 H 4 ) 2 ClGe III ]Pt I Cl with quantum yields of 1.7 % and 3.2 % for the Ge IV –Pt II and Ge III –Pt III isomers, respectively. Conversion of the Ge IV –Pt II isomer into the platinum germyl complex is a rare example of a light-induced transition-metal/main-group-element bond-forming process. Additionally, transient-absorption-spectroscopy studies carried out on the Ge III –Pt III isomer point to a ligand arene–Cl. charge-transfer complex as an intermediate.

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

Intramolecular 1,2 C-H Addition of o -Methyl Groups to Form Unique Ruthenium Pincer Tuck-in Complexes

New RPN H P ligands containing 2,4-xylyl (4mXPN H P) and mesityl (MesPN H P) groups on the phosphorus atoms were synthesized. 4mXPN H P reacts with [(cymene)RuCl 2 ] 2 followed by PMe 3 to produce κ 3 -4mXPN H PRu(PMe 3 )Cl 2 . MesPN H P reacts with [(cymene)RuCl 2 ] 2 to produce monomeric κ 3 -MesPN H PRuCl 2 that reacts with CO forming κ 3 -MesPN H PRu(CO)Cl 2 . Surprisingly, dehydrohalogenation of these complexes results in the activation of ortho methyl groups of the pincer ligands, rather than formation of κ 3 -RPNPRuLCl complexes. This results from transient κ 3 -RPNPRuLCl formation followed by 1,2-addition of an ortho C-H bond across the Ru-amide bond. The transient amide complex of κ 4 -4mXPN H PRu(PMe 3 )Cl was trapped with CO forming κ 3 -4mXPNPRu(PMe 3 )(CO)Cl. In contrast, κ 4 -MesPNHPRu(CO)Cl does not react with ligands to trap the expected amide complex of reverse C-H addition. Instead, CO and PMe 3 displace the chloride ligand forming cationic complexes. In both cases, hemi-lability of the pincer ligand was observed spectroscopically. In conclusion, the new complexes serve as precursors to moderately active catalysts for the acceptorless dehydrogenative coupling of n-butanol.

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

Trapping an Unexpected/Unprecedented Hexanuclear Ce(III) Hydrolysis Product with Neutral 4‐Amino‐1,2,4‐triazole

Using Ce(III) as both a representative lanthanide and actinide analog, the ability of mixtures of acidic and basic azoles to allow direct access to homoleptic N-donor f-element complexes in one pot reactions from hydrated salts as starting materials was examined by reacting mixtures of 4-amino-1,2,4-triazole (4-NH 2 -1,2,4-Triaz), 5-amino-tetrazole (5-NH 2 -HTetaz), and 1,2,3-triazole (1,2,3-HTriaz) in 1 : 1 and 1 : 3 ratios with CeCl 3 ⋅ 7H 2 O, [C 2 mim] 3 [CeCl 6 ] ([C 2 mim] + =1-ethyl-2-methylimidazolium), and Ce(NO 3 ) 3 ⋅ 6H 2 O. Although unsuccessful in our goal, structural analysis revealed that neutral 4-NH 2 -1,2,4-Triaz is structure directing via η 2 μ 2 κ 2 bridging, with the formation of the dinuclear complexes [Ce 2 Cl 2 (μ 2 -4-NH 2 -1,2,4-Triaz) 4 (H 2 O) 8 ]Cl 4 ⋅ 4H 2 O, [Ce 2 (μ 2 -4-NH 2 -1,2,4-Triaz) 4 (4-NH 2 -1,2,4-Triaz) 2 (Cl) 6 ], and [4-NH 2 -1,2,4-HTriaz][Ce 2 (μ 2 -4-NH 2 -1,2,4-Triaz) 2 (μ 2 -NO 3 )(NO 3 ) 6 (H 2 O) 2 ]. When the synthetic conditions favored hydrolysis, the hexanuclear Ce(III) complex [Ce 6 (μ 3 -O) 4 (μ 3 -OH) 2 (μ 3 -Cl) 2 (Cl) 6 (μ 2 -4-NH 2 -1,2,4-Triaz) 12 ] ⋅ 7H 2 O was isolated. This unexpected hydrolysis product represents the first example of a high nuclearity lanthanide complex where all Ln atoms are pairwise connected through 12 N-donor ligands or 12 neutral bridging ligands of any type, a rare example of incorporation of non-oxo coordinating anions in the M 6 X 8 core, and the first reported Ce(III) hexanuclear complex of this type.

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

Influence of residual chlorine on Ru/TiO 2 active sites during CO 2 methanation

Titania-supported ruthenium (Ru/TiO 2 ) is an established catalyst for the hydrogenation of carbon dioxide to methane (Sabatier reaction). Chlorine contamination, owed to the RuCl 3 precursor, is demonstrated to have a detrimental impact on methanation activity. After calcination and reduction the catalyst contains residual chlorine, shown by XPS. An aqueous ammonia wash removes Cl without leaching Ru. The washed catalysts exhibit improvements in CH 4 site-time yields. Low Ru loading catalysts encounter the greatest activity enhancements after washing (~4.5-fold). DFT calculations indicate that chlorine and CO 2 directly compete for adsorption on Ru step sites, with Cl impeding the adsorption of CO 2 at under-coordinated sites and at higher Cl coverages. H 2 -chemisorption/TPR show that Cl removal lowers the onset of low temperature H 2 dissociation on Ru. Finally, DRIFTS provide evidence that the removal of Cl facilitates low temperature dissociative binding of CO 2 , indicated by the formation of surface bound linear CO species.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Cross-sections for 43 Sc, 44 m Sc, and 44 g Sc from two heavy ion reactions

Two different heavy ion reactions were used to produce 43 Sc (t$_{\frac12}$ = 3.891 h), 44g Sc (t$_{\frac12}$ = 4.042 h), and 44m Sc (t$_{\frac12}$ = 58.61 h) among other stable or long-lived chemically separable products. Production cross sections for 19 F + 27 Al and the reverse kinematic reaction 35 Cl + nat B were measured using an MC-SNICS ion source and the Notre Dame FN Tandem Accelerator. 19 F beams from 35 to 60 MeV were produced with beam currents between 40–80 pnA and 35 Cl beams were produced at six entrance energies with comparable beam currents. This work reports nuclear reaction cross sections 27 Al ( 19 F, x) 43 Sc, 27 Al ( 19 F, pn) 44g Sc, and 27 Al ( 19 F, pn) 44m Sc at six energies between 35 and 60 MeV lab energy. Cross sections within the same energy range were measured for 27 Al ( 19 F, 3pn) 42 K and 27 Al ( 19 F, 3p) 43 K. Comparative measurements were performed for the same compound nucleus produced from nat B( 35 Cl, x) 43 Sc, nat B( 35 Cl, pn) 44g Sc, and nat B( 35 Cl, pn) 44m Sc. The measured thin target cross sections show an overestimation by several statistical models for the scandium radioisotopes. This is corroborated by the measured thick target production rates for both entrance channels. This may be due to angular momentum effects of a heavy ion entrance channel compared to light-ion production, but additional work is required to understand this discrepancy. Finally, these measurements demonstrate that the medically useful 43 Sc, 44g Sc, and 44m Sc radioisotopes can be free of the long-lived contaminant 46 Sc without the use of enriched targets, using heavy ion beams and robust target materials.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

Chemical and isotopic evolution of flowback fluids from the Utica Gas Shale Play, Eastern Ohio USA

For this work, hydraulic fracturing flowback fluids were collected from two Utica/Point Pleasant well pads in eastern Ohio. One site was in the wet gas zone (UPPW), while the site ~50 km south consisted of four wells on the same pad in the dry gas zone (UPPS). Samples of input fluids also were collected before and during hydraulic fracturing. Flowback fluids are Na-Ca-Cl brines with total dissolved salt (TDS) concentrations that increase over several months from ~100 to 200 g/L. The slightly higher TDS of the dry gas fluids are in part due to recycled flowback used as input fluids, and in part due to lower volume of water used in hydraulic fracturing. Concentrations of most major ions (Ca 2+ , Mg 2+ , Na + , Sr2 + , Fe, Mn, Cl – , Br – ) are similar for the five wells sampled, although small but systematic changes occur in the major element ratios over time. Most notably, an increase in the Sr/Cl ratio corresponds to an increase in the 87 Sr/ 86 Sr ratio in the fluids, suggesting interactions with a more radiogenic Sr source in the subsurface. Dissolved Ba concentrations and Ra activities were different between the two sites, reflecting a high SO 4 2– fluid used at the UPPW site, and water-rock reactions occurring during hydraulic fracturing at the UPPS site. Water oxygen (δ 18 O) and hydrogen (δD) isotopes for input fluids used in the UPPW4 well and fresh water used for the UPPS wells fall on the Global Meteoric waterline (GMWL). Flowback fluids from both sites are relatively enriched in δ 18 O and δD compared to the input, but do not appear to follow a simple mixing trend, suggesting reaction and isotopic exchange with carbonates and fractionation due to imbibition in the rock. Cl isotopes, δ 37 Cl in the FP fluids varied from ~ –0.43 to +0.13‰, the largest variation was observed in the earlier stages of flowback, while in the later stages δ 37 Cl exhibited a small but systematic increase over time, suggesting diffusion control of isotopic composition. Some of the trace species measured (dissolved Fe, Mn, thiosulfate and organic acids) do not follow the same trends as the major ions, suggesting contributions from input fluids, or microbially mediated reactions are exerting control on their concentrations. Input water chemistry exerts an important control on the Sr and Ba concentrations in flowback water. High SO 4 2– in the input fluids used for hydraulically fracturing the wet gas well leads to precipitation of barite-celestite in flowback fluids.

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

Multi-technique characterization of spray coated and roll-to-roll coated gas diffusion fuel cell electrodes

Here this work reports the characterization of catalyst layer (CL) structure and composition for a set of gas-diffusion electrodes (GDEs) fabricated by different coating methods with the goal of developing a better understanding of CL processing-structure-property-performance relationships. The CL coating techniques used in this study were ultrasonic spray coating, and two roll-to-roll (R2R) methods - gravure and slot die. Scanning transmission electron microscopy (STEM) coupled with X-ray energy dispersive spectroscopy (EDS) analysis of GDE cross-sections provided bulk information, while scanning electron microscopy (SEM) with EDS and X-ray photoelectron spectroscopy (XPS) were used to investigate the near surface and surface composition of the CLs that will be in direct contact with the membrane once the membrane electrode assembly (MEA) is constructed. This study demonstrates that common quantification parameters, namely the F:Pt ratio extracted from cross-sectional STEM-EDS maps and top-down CL measurements with SEM and XPS, along with roughness parameters quantified from SEM micrographs are useful parameters in explaining and potentially predicting performance trends. Additionally, it highlights the importance of understanding key CL surface properties for advancing the manufacturability of high-performance components for polymer electrolyte membrane (PEM) technologies.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2025

First principles investigation of dopants and defect complexes in CdSe$_x$Te$_{1-x}$

Se alloying is a common approach to improve the performance of CdTe solar cells by tuning the bandgap, defect levels, and carrier density. A fundamental understanding of these improvements, specifically the effect of Se alloying on the behavior of defects and dopants in CdTe, remains unclear. Here, in this work, we present a density functional theory (DFT) study of point defect energetics in CdTe and CdSe x Te 1-x with x = 0.25, leading to a comparison of how native defects, dopants (As and Cu), impurities (Cl and O), and related defect complexes behave in CdTe vs CdSe x Te 1-x . Our calculations, performed by combining semi-local and nonlocal hybrid functionals, show a general lowering of the formation energies of native defects as well as substitutional defects formed by As and Cl upon Se addition. For successful p-type doping with As, destabilizing Cl-based defects in the CdSeTe lattice would be essential. We find evidence for some low-energy defect complexes of As, Cl, and O in CdSe 0.25 Te 0.75 . The computed defect formation energies further enable estimates of temperature-dependent defect concentrations and self-consistent Fermi levels. A comparison of defect energetics with the energies of impurity phases reveals that As, Cu, Cl, and O overwhelmingly prefer being segregated to unwanted As 2 O 5 , AsCl 3 , Cd 2 AsCl 2 , and CuO x phases rather than remain at defect sites, but such segregation is less likely to happen in CdSe 0.25 Te 0.75 than in CdTe. Overall, our work presents a list of likely defects and complexes in CdTe and Se-incorporated CdTe, paving the way to explain and mitigate limited dopant activation in experimental observations.

CdTe↗
DOE OSTI2023

Magnetic behavior of manganese chloride on Kagome and honeycomb lattices

The magnetic properties of transparent pink Na 2 Mn 3 Cl 8 and NaMnCl3 are presented. For both phases, the effective magnetic moments are large, while the Curie-Weiss thetas are below 10 K. The compounds crystallize in the trigonal R-3m and R-3 space groups, respectively. A Kagome plane of Mn 2+ octahedrally coordinated to Cl- is found in Na 2 Mn 3 Cl 8 and the material has no apparent magnetic ordering above 1.8 K, while the octahedrally coordinated, honeycomb network of Mn 2+ in NaMnCl 3 orders antiferromagnetically at 6.3 ± 0.2 K. The heat capacity of NaMnCl3 has one transition, consistent with the susceptibility, while Na 2 Mn 3 Cl 8 exhibits a more complex heat capacity with two peaks, at 0.6 K and 1.4 K. A third, broad peak near 6.2 K in the heat capacity of Na 2 Mn 3 Cl 8 is problematic but may be due to the intergrowth of NaMnCl 3 domains.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Thiohalorhabdus methylotropha sp. nov., an extremely halophilic autotrophic methylotiotroph from hypersaline lakes

So far, there have been no reports of trimethylamine (TMA)-utilizing extremely halophilic microorganisms in hypersaline habitats. Our aerobic enrichments at 4 M total Na + with 5 mM TMA inoculated with surface sediments from hypersaline soda (at pH 9.5) or chloride-sulfate (at pH 7) lakes in southwestern Siberia were successful only for the latter. The initial enrichment included both bacteria and haloarchaea but only the bacterial component was able to grow as a pure culture with TMA. Strain Cl-TMA forms a new-species lineage within the genus Thiohalorhabdus which includes extremely halophilic and obligate lithoautotrophic sulfur-oxidizing gammaproteobacteria. Cl-TMA can grow methyloautotrophically utilizing TMA, dimethylamine (DMA) and methanol (MeOH) as the electron donors or chemolithoautotrophically with thiosulfate. Mixotrophic growth was also observed with the three methyl compounds and thiosulfate. Carbon is assimilated autotrophically via the Calvin-Benson-Basham pathway. Unlike the type species of Thiohalorhabdus, T. denitrificans , Cl-TMA was incapable of anaerobic growth via denitrification. The isolate belongs to extreme halophiles growing between 2.5 and 5 M NaCl with an optimum at 3–3.5 M. Genome analysis identified two gene clusters coding for PQQ-dependent methanol dehydrogenases (MxaFI and XoxF), four homologues of the formaldehyde activating enzymes (Faes), a TMA/DMA oxidation locus, and two cluster of genes encoding an N-methylglutamate dehydrogenase pathway (NMGP) for methylamine oxidation. The first steps of C 1 -subtrate conversions are followed by the tetrahydrofolate (THF)-linked and tetrahydromethanopterin (H4MPT)-linked formaldehyde oxidation pathways and two formate dehydrogenases. All of those signatures of methylotrophy were absent in T. denitrificans . In contrast, genes for two key sulfur oxidation enzymes, thiosulfate dehydrogenase TsdAB and sulfide dehydrogenase FccAB, that are present in the type species are missing in Cl-TMA. Thiosulfate is oxidized to sulfate by a combination of an incomplete Sox cycle and an sHdr system. Strain Cl-TMA T (JCM 35977 = UQM 41915) is proposed to be classified as Thiohalorhabdus methylotrophus sp. nov.

59 BASIC BIOLOGICAL SCIENCES↗