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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Mg x Zn 1−x O contact to CuGa 3 Se 5 absorber for photovoltaic and photoelectrochemical devices

Abstract CuGa 3 Se 5 is a promising candidate material with wide band gap for top cells in tandem photovoltaic and photoelectrochemical (PEC) devices. However, traditional CdS contact layers used with other chalcopyrite absorbers are not suitable for CuGa 3 Se 5 due to the higher position of its conduction band (CB) minimum. Mg x Zn 1− x O (MZO) is a transparent oxide with adjustable band gap and CB position as a function of magnesium composition, but its direct application is hindered by CuGa 3 Se 5 surface oxidation. Here, MZO is investigated as a contact (n-type ‘buffer’ or ‘window’) material to CuGa 3 Se 5 absorbers pretreated in Cd 2+ solution, and an onset potential close to 1 V vs reversible hydrogen electrode in 10 mM hexaammineruthenium (III) chloride electrolyte is demonstrated. The Cd 2+ surface treatment changes the chemical composition and electronic structure of the CuGa 3 Se 5 surface, as demonstrated by photoelectron spectroscopy measurements. The performance of CuGa 3 Se 5 absorber with Cd 2+ treated surface in the solid-state test structure depends on the Zn/Mg ratio in the MZO layer. The measured open circuit voltage of 925 mV is promising for tandem PEC water splitting with CuGa 3 Se 5 /MZO top cells.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Quasilinear dispersion in electronic band structure and high Seebeck coefficient in CuFeS 2 -based thermoelectric materials

The earth-abundant natural mineral chalcopyrite CuFeS 2 is a potential n-type thermoelectric material because of its large Seebeck coefficient at high carrier concentrations. For a long time, the large Seebeck coefficient of CuFeS 2 has been attributed to a large electron effective mass, but the reasons for this and the unusual carrier concentration dependent behavior have rarely been discussed. Here, we systematically investigated the special transport behavior of CuFeS 2 and found the classical parabolic band model to be inadequate in explaining it. Our experimental and theoretical studies indicate that there are two flat electronic pockets at the and Z points of the Brillouin zone near the conduction band edge of CuFeS 2 that dominate the charge transport. These electronic pockets result from nonparabolic quasilinearly dispersing bands that give rise to a linear wave vector dependent energy (E ~ k) and a carrier density dependent effective mass (m* ~ m 0 n 1/3 ). Such a strong carrier concentration dependent carrier effective mass results in the high Seebeck coefficient of CuFeS 2 compound under a large carrier density. Here, the work demonstrates that quasilinearly dispersing bands can give strongly enhanced Seebeck coefficient, and could be useful in optimizing the properties of thermoelectric materials.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Electronic structure and exchange interactions in altermagnetic MnGeP 2 in the quasiparticle self-consistent G W approach

The quasiparticle self-consistent 𝐺⁡𝑊 method is used to study the electronic band structure, optical dielectric function, and exchange interactions in chalcopyrite, 𝐼⁢ ‾ 4 ⁢2⁢𝑑, structure MnGeP 2 . The material is found to be an antiferromagnetic semiconductor with a lowest direct gap of 2.44 eV at the Γ point and a lower indirect gap of 1.87 eV from Γ to 𝑀. The material is an altermagnet because the two magnetic atoms of opposite spin are related by a twofold rotation operation perpendicular to the main fourfold rotation inversion axis. The spin splittings along a low symmetry line like 𝑃⁢𝑁 is sizable while at k points on the diagonal mirror planes or on the twofold symmetry axes the spin splitting is zero. The exchange interactions are calculated using a linear response approach. The antiferromagnetic exchange interaction between nearest neighbors in the primitive unit cell is dominating and found to be slightly decreasing upon carrier doping but not sufficiently to change the interaction to become ferromagnetic. The bare (noninteracting) and interacting transverse spin susceptibilities, which provide interatomic site exchange interactions after averaging over the muffin-tin spheres, are calculated from the 𝐺⁡𝑊 band structure and wave functions. From these exchange interactions, the spin wave spectra are obtained along the high symmetry lines and the Néel temperature is calculated using the mean-field and Tyablikov estimations. The dielectric function and the optical absorption spectra are calculated including excitonic effects using the Bethe Salpeter equation. The exchange interactions around Mn Ge defect sites is also studied. While we find it can generate ferromagnetic interactions with neighboring spins, we did not find direct evidence of producing an overall ferromagnetic phase. First, if Mn antisites are introduced by exchanging Mn with a nearby Ge, the interactions stay largely antiferromagnetic. Second, when we add additional Mn, in other words in Mn-rich stoichiometry, the Mn Ge antisites produce a strong ferromagnetic interaction primarily with the Mn in the same basal plane but weaker ferromagnetic interaction with adjacent plane Mn. The interactions between regular lattice Mn stay antiferromagnetic as before and thus favor keeping the antiferromagnetic order along the [001] direction. Adding Mn antisites, however, does lead to a metallic band structure.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Cobalt mineralogy at the Iron Creek deposit, Idaho cobalt belt, USA: Implications for domestic critical mineral production

Current U.S. policies aim to establish domestic supply chains of critical minerals for the energy transition. The Iron Creek deposit in the Idaho cobalt belt (ICB) is one of the most promising cobalt (Co) targets. Our case study illustrates the importance of mineralogy in strategic evaluations of critical mineral potential. Most of the Co at Iron Creek occurs as Fe substitution in pyrite, with lattice-bound and inclusion-hosted Ag, As, Bi, Ni, Pb, Se, Te ± trace Au and Sb. Cobalt also occurs in minor cattierite-vaesite. The Co minerals are intergrown with Co-poor chalcopyrite hosting Cu ± minor In and Zn. Worldwide, most Co is recovered from deposits mineralogically distinct from the ICB, and the United States currently lacks infrastructure to recover this Co and its associated metals. ICB ore minerals could be processed by autoclave, roaster, smelter, bioleach, or heap leach. Recovery of the Ag, As, Au, Bi, In, Pb, Se, Te, and Zn would be costly by autoclave, and construction of a custom smelter for ICB ores is likely uneconomic, so these elements would become waste irrespective of criticality. The Co-Fe and Co-As sulfide minerals are most suitable for Co and Ni recovery by a hydrometallurgical autoclave process, with potential pretreatment of cobaltiferous pyrite/arsenopyrite in an inert-atmosphere roaster, in new domestic or anticipated international facilities. The ICB is the second largest known Co resource in the United States. Consideration of ore mineralogy in the ICB is essential in strategies for domestic production.

58 GEOSCIENCES↗
DOE OSTI2020

Materials Data on CdSnSb2 by Materials Project

CdSnSb2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Cd2+ is bonded to four equivalent Sb3- atoms to form CdSb4 tetrahedra that share corners with four equivalent CdSb4 tetrahedra and corners with eight equivalent SnSb4 tetrahedra. All Cd–Sb bond lengths are 2.86 Å. Sn4+ is bonded to four equivalent Sb3- atoms to form SnSb4 tetrahedra that share corners with four equivalent SnSb4 tetrahedra and corners with eight equivalent CdSb4 tetrahedra. All Sn–Sb bond lengths are 2.87 Å. Sb3- is bonded to two equivalent Cd2+ and two equivalent Sn4+ atoms to form corner-sharing SbCd2Sn2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuBS2 by Materials Project

CuBS2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with four equivalent CuS4 tetrahedra and corners with eight equivalent BS4 tetrahedra. All Cu–S bond lengths are 2.28 Å. B3+ is bonded to four equivalent S2- atoms to form BS4 tetrahedra that share corners with four equivalent BS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All B–S bond lengths are 1.95 Å. S2- is bonded to two equivalent Cu1+ and two equivalent B3+ atoms to form corner-sharing SCu2B2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlAgSe2 by Materials Project

AgAlSe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ag1+ is bonded to four equivalent Se2- atoms to form AgSe4 tetrahedra that share corners with four equivalent AgSe4 tetrahedra and corners with eight equivalent AlSe4 tetrahedra. All Ag–Se bond lengths are 2.68 Å. Al3+ is bonded to four equivalent Se2- atoms to form AlSe4 tetrahedra that share corners with four equivalent AlSe4 tetrahedra and corners with eight equivalent AgSe4 tetrahedra. All Al–Se bond lengths are 2.43 Å. Se2- is bonded to two equivalent Ag1+ and two equivalent Al3+ atoms to form corner-sharing SeAl2Ag2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlAgTe2 by Materials Project

AgAlTe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ag1+ is bonded to four equivalent Te2- atoms to form AgTe4 tetrahedra that share corners with four equivalent AgTe4 tetrahedra and corners with eight equivalent AlTe4 tetrahedra. All Ag–Te bond lengths are 2.82 Å. Al3+ is bonded to four equivalent Te2- atoms to form AlTe4 tetrahedra that share corners with four equivalent AlTe4 tetrahedra and corners with eight equivalent AgTe4 tetrahedra. All Al–Te bond lengths are 2.66 Å. Te2- is bonded to two equivalent Ag1+ and two equivalent Al3+ atoms to form corner-sharing TeAl2Ag2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlCuS2 by Materials Project

CuTlS2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with four equivalent CuS4 tetrahedra and corners with eight equivalent TlS4 tetrahedra. All Cu–S bond lengths are 2.31 Å. Tl3+ is bonded to four equivalent S2- atoms to form TlS4 tetrahedra that share corners with four equivalent TlS4 tetrahedra and corners with eight equivalent CuS4 tetrahedra. All Tl–S bond lengths are 2.64 Å. S2- is bonded to two equivalent Cu1+ and two equivalent Tl3+ atoms to form corner-sharing STl2Cu2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlCuSe2 by Materials Project

CuTlSe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CuSe4 tetrahedra and corners with eight equivalent TlSe4 tetrahedra. All Cu–Se bond lengths are 2.43 Å. Tl3+ is bonded to four equivalent Se2- atoms to form TlSe4 tetrahedra that share corners with four equivalent TlSe4 tetrahedra and corners with eight equivalent CuSe4 tetrahedra. All Tl–Se bond lengths are 2.76 Å. Se2- is bonded to two equivalent Cu1+ and two equivalent Tl3+ atoms to form corner-sharing SeTl2Cu2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiBO2 by Materials Project

LiBO2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Li–O bond lengths are 1.98 Å. B3+ is bonded to four equivalent O2- atoms to form corner-sharing BO4 tetrahedra. All B–O bond lengths are 1.49 Å. O2- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgSiN2 by Materials Project

MgSiN2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent N3- atoms to form MgN4 tetrahedra that share corners with four equivalent MgN4 tetrahedra and corners with eight equivalent SiN4 tetrahedra. All Mg–N bond lengths are 2.11 Å. Si4+ is bonded to four equivalent N3- atoms to form SiN4 tetrahedra that share corners with four equivalent SiN4 tetrahedra and corners with eight equivalent MgN4 tetrahedra. All Si–N bond lengths are 1.76 Å. N3- is bonded to two equivalent Mg2+ and two equivalent Si4+ atoms to form corner-sharing NMg2Si2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BeCN2 by Materials Project

BeCN2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Be2+ is bonded to four equivalent N3- atoms to form BeN4 tetrahedra that share corners with four equivalent BeN4 tetrahedra and corners with eight equivalent CN4 tetrahedra. All Be–N bond lengths are 1.70 Å. C4+ is bonded to four equivalent N3- atoms to form CN4 tetrahedra that share corners with four equivalent CN4 tetrahedra and corners with eight equivalent BeN4 tetrahedra. All C–N bond lengths are 1.50 Å. N3- is bonded to two equivalent Be2+ and two equivalent C4+ atoms to form corner-sharing NBe2C2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BeSiN2 by Materials Project

BeSiN2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Be2+ is bonded to four equivalent N3- atoms to form BeN4 tetrahedra that share corners with four equivalent BeN4 tetrahedra and corners with eight equivalent SiN4 tetrahedra. All Be–N bond lengths are 1.78 Å. Si4+ is bonded to four equivalent N3- atoms to form SiN4 tetrahedra that share corners with four equivalent SiN4 tetrahedra and corners with eight equivalent BeN4 tetrahedra. All Si–N bond lengths are 1.75 Å. N3- is bonded to two equivalent Be2+ and two equivalent Si4+ atoms to form corner-sharing NBe2Si2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InAgS2 by Materials Project

AgInS2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ag1+ is bonded to four equivalent S2- atoms to form AgS4 tetrahedra that share corners with four equivalent AgS4 tetrahedra and corners with eight equivalent InS4 tetrahedra. All Ag–S bond lengths are 2.58 Å. In3+ is bonded to four equivalent S2- atoms to form InS4 tetrahedra that share corners with four equivalent InS4 tetrahedra and corners with eight equivalent AgS4 tetrahedra. All In–S bond lengths are 2.51 Å. S2- is bonded to two equivalent Ag1+ and two equivalent In3+ atoms to form corner-sharing SIn2Ag2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiInSe2 by Materials Project

LiInSe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Li1+ is bonded to four equivalent Se2- atoms to form LiSe4 tetrahedra that share corners with four equivalent LiSe4 tetrahedra and corners with eight equivalent InSe4 tetrahedra. All Li–Se bond lengths are 2.58 Å. In3+ is bonded to four equivalent Se2- atoms to form InSe4 tetrahedra that share corners with four equivalent InSe4 tetrahedra and corners with eight equivalent LiSe4 tetrahedra. All In–Se bond lengths are 2.63 Å. Se2- is bonded to two equivalent Li1+ and two equivalent In3+ atoms to form corner-sharing SeLi2In2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InAgSe2 by Materials Project

AgInSe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ag1+ is bonded to four equivalent Se2- atoms to form AgSe4 tetrahedra that share corners with four equivalent AgSe4 tetrahedra and corners with eight equivalent InSe4 tetrahedra. All Ag–Se bond lengths are 2.68 Å. In3+ is bonded to four equivalent Se2- atoms to form InSe4 tetrahedra that share corners with four equivalent InSe4 tetrahedra and corners with eight equivalent AgSe4 tetrahedra. All In–Se bond lengths are 2.65 Å. Se2- is bonded to two equivalent Ag1+ and two equivalent In3+ atoms to form corner-sharing SeIn2Ag2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiInTe2 by Materials Project

LiInTe2 is Chalcopyrite structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Li1+ is bonded to four equivalent Te2- atoms to form LiTe4 tetrahedra that share corners with four equivalent LiTe4 tetrahedra and corners with eight equivalent InTe4 tetrahedra. All Li–Te bond lengths are 2.78 Å. In3+ is bonded to four equivalent Te2- atoms to form InTe4 tetrahedra that share corners with four equivalent InTe4 tetrahedra and corners with eight equivalent LiTe4 tetrahedra. All In–Te bond lengths are 2.84 Å. Te2- is bonded to two equivalent Li1+ and two equivalent In3+ atoms to form corner-sharing TeLi2In2 tetrahedra.

36 MATERIALS SCIENCE↗