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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Si(PbSe2)2 by Materials Project

SiPb2Se4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.90–3.67 Å. In the second Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.95–3.74 Å. Si4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are three shorter (2.30 Å) and one longer (2.31 Å) Si–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom. In the second Se2- site, Se2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom. In the third Se2- site, Se2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom. In the fourth Se2- site, Se2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(CN2)2 by Materials Project

SiC2N4 crystallizes in the cubic Pn-3m space group. The structure is three-dimensional. Si4+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Si–N bond lengths are 1.69 Å. C4+ is bonded in a linear geometry to two equivalent N3- atoms. Both C–N bond lengths are 1.21 Å. N3- is bonded in a linear geometry to one Si4+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(PbS2)2 by Materials Project

SiPb2S4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.84–3.38 Å. In the second Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.80–3.51 Å. Si4+ is bonded in a tetrahedral geometry to four S2- atoms. There are a spread of Si–S bond distances ranging from 2.13–2.15 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom. In the second S2- site, S2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom. In the third S2- site, S2- is bonded in a distorted single-bond geometry to three Pb2+ and one Si4+ atom. In the fourth S2- site, S2- is bonded in a distorted single-bond geometry to four Pb2+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(CO)2 by Materials Project

Si(CO)2 crystallizes in the orthorhombic Immm space group. The structure is zero-dimensional and consists of two dimethoxysilicon;silicon molecules and four formaldehyde molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(H3C)2 by Materials Project

Si(CH3)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four methylsilicon molecules; eight silane, dimethyl- molecules; and four trimethylsilyl radical molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(Ag4S3)2 by Materials Project

Ag8SiS6 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are eight inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.52–2.55 Å. In the second Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.59–2.96 Å. In the third Ag1+ site, Ag1+ is bonded in a linear geometry to two S2- atoms. There are one shorter (2.45 Å) and one longer (2.47 Å) Ag–S bond lengths. In the fourth Ag1+ site, Ag1+ is bonded to four S2- atoms to form distorted AgS4 tetrahedra that share corners with two equivalent SiS4 tetrahedra. There are a spread of Ag–S bond distances ranging from 2.64–2.74 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.48–3.09 Å. In the sixth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.56–2.64 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.57–2.96 Å. In the eighth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.51–2.64 Å. Si4+ is bonded to four S2- atoms to form SiS4 tetrahedra that share corners with two equivalent AgS4 tetrahedra. There are two shorter (2.15 Å) and two longer (2.16 Å) Si–S bond lengths. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to four Ag1+ and one Si4+ atom. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four Ag1+ and one Si4+ atom. In the third S2- site, S2- is bonded in a distorted tetrahedral geometry to three Ag1+ and one Si4+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to five Ag1+ atoms. In the fifth S2- site, S2- is bonded in a 6-coordinate geometry to six Ag1+ atoms. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to four Ag1+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(H3C)2 by Materials Project

Si(CH3)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two dimethylsilane molecules, two silicon molecules, and four trimethylsilyl radical molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(GeN2)2 by Materials Project

SiGe2N4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ge4+ is bonded to six equivalent N3- atoms to form GeN6 octahedra that share corners with six equivalent SiN4 tetrahedra and edges with six equivalent GeN6 octahedra. All Ge–N bond lengths are 2.01 Å. Si4+ is bonded to four equivalent N3- atoms to form SiN4 tetrahedra that share corners with twelve equivalent GeN6 octahedra. The corner-sharing octahedral tilt angles are 56°. All Si–N bond lengths are 1.81 Å. N3- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Ge4+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(NF3)2 by Materials Project

N2SiF6 is Calaverite structured and crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of four ammonia molecules and two SiF6 clusters. In each SiF6 cluster, Si4+ is bonded in an octahedral geometry to six equivalent F1- atoms. All Si–F bond lengths are 1.71 Å. F1- is bonded in a single-bond geometry to one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(NF3)2 by Materials Project

N2SiF6 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight ammonia molecules and four SiF6 clusters. In each SiF6 cluster, Si4+ is bonded in an octahedral geometry to six equivalent F1- atoms. All Si–F bond lengths are 1.71 Å. F1- is bonded in a single-bond geometry to one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(H3C)2 by Materials Project

Si(CH3)2 crystallizes in the monoclinic C2 space group. The structure is zero-dimensional and consists of sixteen dimethylsilane molecules, four silicon molecules, and eight trimethylsilyl radical molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Multicaloric Cryocooling Using Heavy Rare-Earth Free La(Fe,Si) 13 -Based Compounds

The transition toward a carbon-neutral society based on renewable energies goes hand in hand with the availability of energy-efficient technologies. Here, magnetocaloric cooling is a very promising refrigeration technology to fulfill this role regarding cryogenic gas liquefaction. However, the current reliance on highly resource critical, heavy rare-earth-based compounds as magnetocaloric material makes global usage unsustainable. Here, we aim to mitigate this limitation through the utilization of a multicaloric cooling concept, which uses the external stimuli of isotropic pressure and magnetic field to tailor and induce magnetostructural phase transitions associated with large caloric effects. In this study, La 0.7 Ce 0.3 Fe 11.6 Si 1.4 is used as a nontoxic, low-cost, low-criticality multiferroic material to explore the potential, challenges, and peculiarities of multicaloric cryocooling, achieving maximum isothermal entropy changes up to −28 J (kg K) −1 in the temperature range from 190 K down to 30 K. Thus, the multicaloric cooling approach offers an additional degree of freedom to tailor the phase transition properties and may lead to energy-efficient and environmentally friendly gas liquefaction based on designed-for-purpose, noncritical multiferroic materials.

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

Materials Data on Hg2Pb(SI)2 by Materials Project

Hg2Pb(SI)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Hg2+ is bonded to two equivalent S2- and four I1- atoms to form a mixture of distorted corner, edge, and face-sharing HgS2I4 octahedra. The corner-sharing octahedra tilt angles range from 0–63°. There are one shorter (2.43 Å) and one longer (2.44 Å) Hg–S bond lengths. There are two shorter (3.38 Å) and two longer (3.51 Å) Hg–I bond lengths. Pb2+ is bonded in a 7-coordinate geometry to four equivalent S2- and three I1- atoms. All Pb–S bond lengths are 3.05 Å. There are one shorter (3.30 Å) and two longer (3.56 Å) Pb–I bond lengths. S2- is bonded in a 2-coordinate geometry to two equivalent Hg2+ and two equivalent Pb2+ atoms. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded to four equivalent Hg2+ and one Pb2+ atom to form edge-sharing IHg4Pb square pyramids. In the second I1- site, I1- is bonded in a 4-coordinate geometry to four equivalent Pb2+ atoms. In the third I1- site, I1- is bonded in a body-centered cubic geometry to eight equivalent Hg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3Re3(SI)4 by Materials Project

Cs3Re3(SI)4 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cs1+ is bonded in a distorted q6 geometry to four equivalent S2- and six I1- atoms. All Cs–S bond lengths are 3.72 Å. There are two shorter (4.05 Å) and four longer (4.10 Å) Cs–I bond lengths. Re3+ is bonded to four equivalent S2- and one I1- atom to form edge-sharing ReS4I square pyramids. All Re–S bond lengths are 2.43 Å. The Re–I bond length is 2.83 Å. S2- is bonded in a 6-coordinate geometry to three equivalent Cs1+ and three equivalent Re3+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted single-bond geometry to four equivalent Cs1+ and one Re3+ atom. In the second I1- site, I1- is bonded to six equivalent Cs1+ atoms to form distorted corner-sharing ICs6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag7(SI)2 by Materials Project

Ag7(SI)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are seven inequivalent Ag sites. In the first Ag site, Ag is bonded to three equivalent Ag and three equivalent I atoms to form distorted AgAg3I3 octahedra that share corners with three equivalent IAg4 trigonal pyramids and edges with six equivalent AgAg3I3 octahedra. There are a spread of Ag–Ag bond distances ranging from 2.88–3.06 Å. There are a spread of Ag–I bond distances ranging from 2.95–3.17 Å. In the second Ag site, Ag is bonded in a distorted linear geometry to one S and one I atom. The Ag–S bond length is 2.41 Å. The Ag–I bond length is 2.68 Å. In the third Ag site, Ag is bonded in a 4-coordinate geometry to one S and three equivalent I atoms. The Ag–S bond length is 2.53 Å. There are a spread of Ag–I bond distances ranging from 2.82–3.10 Å. In the fourth Ag site, Ag is bonded in a distorted single-bond geometry to three equivalent Ag and one I atom. The Ag–I bond length is 2.81 Å. In the fifth Ag site, Ag is bonded in a linear geometry to two S atoms. There are one shorter (2.42 Å) and one longer (2.47 Å) Ag–S bond lengths. In the sixth Ag site, Ag is bonded in a bent 150 degrees geometry to two equivalent S atoms. There are one shorter (2.43 Å) and one longer (2.44 Å) Ag–S bond lengths. In the seventh Ag site, Ag is bonded in a 3-coordinate geometry to three equivalent S atoms. There are a spread of Ag–S bond distances ranging from 2.51–2.67 Å. There are two inequivalent S sites. In the first S site, S is bonded in a distorted see-saw-like geometry to four Ag atoms. In the second S site, S is bonded in a distorted pentagonal planar geometry to five Ag atoms. There are two inequivalent I sites. In the first I site, I is bonded to four Ag atoms to form distorted IAg4 trigonal pyramids that share corners with three equivalent AgAg3I3 octahedra and corners with six equivalent IAg4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 58–63°. In the second I site, I is bonded in a rectangular see-saw-like geometry to four Ag atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag9(SI)4 by Materials Project

Ag9(SI)4 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are nine inequivalent Ag+1.33+ sites. In the first Ag+1.33+ site, Ag+1.33+ is bonded in a 6-coordinate geometry to three equivalent S2- and three equivalent I1- atoms. All Ag–S bond lengths are 2.64 Å. There are one shorter (3.06 Å) and two longer (3.39 Å) Ag–I bond lengths. In the second Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ag–I bond distances ranging from 2.95–3.15 Å. In the third Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are two shorter (2.97 Å) and four longer (3.06 Å) Ag–I bond lengths. In the fourth Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Ag–I bond distances ranging from 2.95–3.13 Å. In the fifth Ag+1.33+ site, Ag+1.33+ is bonded to three equivalent S2- and three equivalent I1- atoms to form a mixture of distorted corner and edge-sharing AgS3I3 octahedra. The corner-sharing octahedra tilt angles range from 6–9°. There are two shorter (2.64 Å) and one longer (2.65 Å) Ag–S bond lengths. There are one shorter (3.06 Å) and two longer (3.34 Å) Ag–I bond lengths. In the sixth Ag+1.33+ site, Ag+1.33+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Ag–S bond distances ranging from 2.51–3.05 Å. In the seventh Ag+1.33+ site, Ag+1.33+ is bonded in a 3-coordinate geometry to three S2- atoms. There are two shorter (2.48 Å) and one longer (2.75 Å) Ag–S bond lengths. In the eighth Ag+1.33+ site, Ag+1.33+ is bonded in a distorted bent 120 degrees geometry to three equivalent S2- atoms. There are two shorter (2.45 Å) and one longer (3.44 Å) Ag–S bond lengths. In the ninth Ag+1.33+ site, Ag+1.33+ is bonded to six S2- atoms to form distorted edge-sharing AgS6 octahedra. There are a spread of Ag–S bond distances ranging from 2.53–3.03 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to six Ag+1.33+ atoms to form distorted SAg6 octahedra that share corners with three equivalent IAg6 octahedra, edges with three equivalent IAg6 octahedra, and edges with six equivalent SAg6 octahedra. The corner-sharing octahedra tilt angles range from 17–21°. In the second S2- site, S2- is bonded to six Ag+1.33+ atoms to form distorted SAg6 octahedra that share corners with three equivalent IAg6 octahedra, edges with three equivalent IAg6 octahedra, and edges with six equivalent SAg6 octahedra. The corner-sharing octahedra tilt angles range from 18–22°. In the third S2- site, S2- is bonded in a 3-coordinate geometry to five Ag+1.33+ atoms. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to seven Ag+1.33+ atoms. There are four inequivalent I1- sites. In the first I1- site, I1- is bonded to six Ag+1.33+ atoms to form IAg6 octahedra that share corners with three equivalent SAg6 octahedra, corners with three equivalent IAg6 octahedra, edges with three equivalent SAg6 octahedra, and edges with nine IAg6 octahedra. The corner-sharing octahedra tilt angles range from 3–22°. In the second I1- site, I1- is bonded to six Ag+1.33+ atoms to form a mixture of corner and edge-sharing IAg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third I1- site, I1- is bonded to six Ag+1.33+ atoms to form a mixture of corner and edge-sharing IAg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fourth I1- site, I1- is bonded to six Ag+1.33+ atoms to form IAg6 octahedra that share corners with three equivalent SAg6 octahedra, corners with three equivalent IAg6 octahedra, edges with three equivalent SAg6 octahedra, and edges with nine IAg6 octahedra. The corner-sharing octahedra tilt angles range from 3–21°.

36 MATERIALS SCIENCE↗
DOE OSTI2024

In Situ Prediction of Microstructure and Mechanical Properties in Laser-Remelted Al-Si Alloys: Towards Enhanced Additive Manufacturing

Laser surface remelting of aluminum alloys has emerged as a promising technique to enhance mechanical properties through refined microstructures. This process involves rapid cooling rates ranging from 10 3 to 10 8 °C/s, which increase solid solubility within aluminum alloys, shifting their eutectic composition to a larger value of silicon content. Consequently, the resulting microstructure combines a strengthened aluminum matrix with silicon fibers. This study focuses on the laser scanning of Al-Si aluminum alloy to reduce the size of aluminum matrix spacings and transform fibrous silicon particles from micrometer to nanometer dimensions. Analysis revealed that the eutectic structure contained 17.55% silicon by weight, surpassing the equilibrium eutectic composition of 12.6% silicon. Microstructure dimensions within the molten zones, termed ‘melt pools’, were extensively examined using Scanning Electron Microscopy (SEM) at intervals of approximately 20 μm from the surface. A notable increase in hardness, exceeding 50% compared to the base plate, was observed in the melt pool regions. Thus, it is exemplified that laser surface remelting introduces a novel strengthening mechanism in the alloy. Moreover, this study develops an in situ method for predicting melt pool properties and dimensions. A predictive model is proposed, correlating energy density and spectral signals emitted during laser remelting with mechanical properties and melt pool dimensions. This method significantly reduces characterization time from days to seconds, offering a streamlined approach for future studies in additive manufacturing.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Effects of Plasma Etching on Dopant Compensation between p- and n-Type Poly-Si Fingers in Passivated Interdigitated Back Contact Solar Cells

Efficiencies surpassing 26% have been achieved for single-junction Si solar cells based on the interdigitated back contact (IBC) architecture. However, the possibility of lateral shunting between the doped fingers has limited industrial adoption thus far. To avoid this possibility of shunt, complicated patterning techniques of the doped rear fingers have been developed, but spreading can still occur through multiple pathways during cell processing. Patterning can be simplified by using masked plasma-enhanced chemical vapor deposition (PECVD), but spreading during deposition will also lead to contamination of the isolation region between doped fingers. We significantly reduce the effect of this spreading through a short, gentle plasma etching step, which enables a trap-assisted compensation mechanism to take effect more easily than without the plasma etch. These two effects combined allow for the use of a simple patterning technique while still maintaining a highly resistive region between the doped fingers, and will reduce the complexity of IBC cell fabrication overall.

atom probe↗