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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Processing and properties of PSZT 95/5 ceramics with varying Ti and Nb substitution

Niobium doped lead-tin-zirconate-titanate ceramics near the PZT 95/5 orthorhombic AFE – rhombohedral FE morphotropic phase boundary Pb 1-0.5y (Zr 0.865-x Ti x Sn 0.135 ) 1-y Nb y O 3 were prepared according to a 2 2+1 factorial design with x = 0.05, 0.07 and y = 0.0155, 0.0195. The ceramics were prepared by a traditional solid-state synthesis route and sintered to near full density at 1250°C for 6 hours. All compositions were ~98% dense with no detectable secondary phases by XRD. The ceramics exhibited equiaxed grains with intergranular porosity and grain size was ~5 μm, decreasing with niobium substitution. Compositions exhibited remnant polarization values of ~32 μC/cm 2 , increasing with Ti substitution. Depolarization by the hydrostatic pressure induced FE-AFE phase transition was drastically affected by variation of the Ti and Nb substitution, increasing at a rate of 113 MPa / 1% Ti and 21 MPa / 1% Nb. Total depolarization output was insensitive to the change in Ti and Nb substitution, ~32.8 μC/cm 2 for the PSZT ceramics. The R3c-R3m and R3m-Pm3m phase transition temperatures on heating ranged from 90 to 105°C and 183 to 191°C, respectively. Ti substitution stabilized the R3c and R3m phases to higher temperatures, while Nb substitution stabilized the Pm3m phase to lower temperatures. Thermal hysteresis of the phase transitions was also observed in the ceramics, with transition temperature on cooling being as much as 10°C lower.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Real-Time Investigation of Sn(II) Oxidation in Pb-Free Halide Perovskites by X-ray Absorption and Mössbauer Spectroscopy

Sn(II) halide perovskites are a less toxic alternative to Pb-based materials in perovskite solar cells, but oxidation to Sn(IV) introduces additional degradation pathways. Improving stability requires mechanistic pictures of O 2 - and H 2 O-induced degradation and their synergy. In this work, we demonstrate that X-ray absorption spectroscopy reports the average valency of the bulk material, allowing oxidation kinetics to be measured from minutes to days. Optical and X-ray diffraction studies demonstrate the challenge of isolating oxidative degradation with techniques lacking element specificity and oxidation state sensitivity. Finally, 119Sn Mössbauer spectroscopy is presented as a lab-based technique capable of providing information on valency and speciation throughout oxidation.

14 SOLAR ENERGY↗
DOE OSTI2020

Bayesian inference of nuclear symmetry energy from measured and imagined neutron skin thickness in Sn 116 , 118 , 120 , 122 , 124 , 130 , 132 , Pb 208 , and Ca 48

The neutron skin thickness Δr np in heavy nuclei has been known as one of the most sensitive terrestrial probes of the nuclear symmetry energy E sym (ρ) around $\frac{2}{3}$ of the saturation density ρ 0 of nuclear matter. Existing neutron skin data mostly from hadronic observables suffer from large uncertainties and their extraction from experiments are often strongly model dependent. While waiting eagerly for the promised model-independent and high-precision neutron skin data for 208 Pb and 48 Ca from the parity-violating electron scattering experiments (PREX-II and CREX at JLab as well as MREX at MESA), within the Bayesian statistical framework using the Skyrme-Hartree-Fock model we infer the posterior probability distribution functions (PDFs) of the slope parameter L of the nuclear symmetry energy at ρ 0 from imagined Δr np ( 208 Pb)=0.15, 0.20, and 0.30 fm with a 1σ error bar of 0.02, 0.04, and 0.06 fm, respectively, as well as Δr np ( 48 Ca)=0.12, 0.15, and 0.25 fm, with different 1σ error bar of 0.01 and 0.02 fm, respectively. The results are compared with the PDFs of L inferred using the same approach from the available Δr np data for 116, 118, 120, 122, 124, 130, 132 Sn from hadronic probes. They are also compared with results from a recent Bayesian analysis of the radius and tidal deformability data of canonical neutron stars from GW170817 and NICER. The neutron skin data for Sn isotopes gives L = 45.5 $^{+ 26.5}_{-21.6}$ MeV surrounding its mean value or L = 53 . 4 $^{+ 18.6}_{ -29.5}$ MeV surrounding its maximum a posteriori value, respectively, with the latter smaller than but consistent with the L = 66 $^{+ 12}_{-20}$ MeV from the neutron star data within their 68% confidence intervals. We found that Δr np = 0.17 –0.18 fm in 208 Pb with an error bar of about 0.02 fm leads to a PDF of L compatible with that from analyzing the Sn data. To provide additionally useful information on L extracted from the Δr np of Sn isotopes, the experimental error bar of Δr np in 208 Pb should be at least smaller than 0.06 fm aimed by some current experiments. In addition, the Δr np ( 48 Ca) needs to be larger than 0.15 fm but smaller than 0.25 fm to be compatible with the Sn and/or neutron star results. To further improve our current knowledge about L and distinguish its PDFs in the examples considered, even higher precisions leading to significantly less than ±20 MeV error bars for L at 68% confidence level are necessary.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Structural, Optical, and Electronic Properties of Two Quaternary Chalcogenide Semiconductors: Ag 2 SrSiS 4 and Ag 2 SrGeS 4

Quaternary chalcogenide materials have long been a source of semiconductors for optoelectronic applications. Recent studies on the I2-II-IV-X4 (I = Ag, Cu, Li; II = Ba, Sr, Eu, Pb; IV = Si, Ge, Sn; X = S, Se) materials have shown particular versatility and promise among these compounds. These semiconductors take advantage of a diverse bonding scheme and chemical differences among cations to target a degree of anti-site defect resistance. Within this set of compounds, the materials containing both Ag and Sr have not been experimentally studied and leave a gap in the full understanding of the family. Here, we have synthesized powders and single crystals of two Ag- and Sr-containing compounds, Ag 2 SrSiS 4 and Ag 2 SrGeS 4 , each found to form in the tetragonal I4¯2m structure of Ag 2 BaGeS 4 . During the synthesis targeting the title compounds, two additional materials, Ag 2 Sr 3 Si 2 S 8 and Ag 2 Sr 3 Ge 2 S 8 , have also been identified. Furthermore, these cubic compounds represent impurity phases during the synthesis of Ag 2 SrSiS 4 and Ag 2 SrGeS 4 . We show through hybrid density functional theory calculations that Ag 2 SrSiS 4 and Ag 2 SrGeS 4 have highly dispersive band edge states and indirect band gaps, experimentally measured as 2.08(1) and 1.73(2) eV, respectively. Second-harmonic generation measurements on Ag 2 SrSiS 4 and Ag 2 SrGeS 4 powders show frequency doubling capabilities in the near-infrared range.

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

Monolithic Two-Terminal All-Perovskite Tandem Solar Cells with Power Conversion Efficiency Exceeding 21%

Monolithic two-terminal (2-T) all-perovskite tandem solar cells are a promising candidate for the next generation solar cells with ultrahigh efficiency and low fabrication cost. Here, we report on the fabrication of 2-T all-perovskite tandem solar cells consisting of solution-processed wide-bandgap and low-bandgap perovskite subcells connected by a vacuum processed interconnection layer. We employed a bulk-passivation strategy to enlarge the grain size, increase carrier mobilities, reduce electronic disorder, and suppress trap-assisted recombination in the low bandgap mixed Sn-Pb perovskite films, which leads to improved performance of low bandgap perovskite solar cells with an absorber thickness over 750 nm. This advance in high-quality low-bandgap perovskite layers enables the fabrication of efficient 2-T all-perovskite solar cells with power conversion efficiencies of more than 21% and decent stability. Our approach provides a suitable pathway to realize ultra-high efficiency 2-T all-perovskite tandem solar cells.

14 SOLAR ENERGY↗
DOE OSTI2020

Materials Data on Sn3TePb4O13 by Materials Project

Pb4Sn3TeO13 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to seven O2- atoms to form distorted PbO7 hexagonal pyramids that share corners with three PbO7 hexagonal pyramids, edges with three PbO7 hexagonal pyramids, edges with two equivalent TeO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.32–2.72 Å. In the second Pb2+ site, Pb2+ is bonded to seven O2- atoms to form distorted PbO7 hexagonal pyramids that share corners with three equivalent PbO7 hexagonal pyramids, edges with three equivalent PbO7 hexagonal pyramids, and edges with six equivalent SnO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.40–2.68 Å. Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with two equivalent TeO6 octahedra, corners with four equivalent SnO6 octahedra, and edges with six PbO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 42–49°. There are a spread of Sn–O bond distances ranging from 2.07–2.16 Å. Te6+ is bonded to six O2- atoms to form TeO6 octahedra that share corners with six equivalent SnO6 octahedra and edges with six equivalent PbO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 42–43°. There is three shorter (1.95 Å) and three longer (1.97 Å) Te–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a tetrahedral geometry to four Pb2+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Pb2+ and two equivalent Sn4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Pb2+, one Sn4+, and one Te6+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Pb2+ and two equivalent Sn4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Pb2+, one Sn4+, and one Te6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Buried interface modulation via $\mathrm{PEDOT:PSS}$ ionic exchange for the Sn-Pb mixed perovskite based solar cells

To apply Sn-Pb mixed perovskite solar cells for highly efficient single- or multi-junction devices, understanding device-specific buried interfaces is necessary. Poly [3,4-ethylenedioxythiophene]:poly[styrene sulfonate] (PEDOT:PSS) is primarily used as a hole transport layer in Sn-Pb mixed perovskite solar cells. However, the spatial heterogeneity of PEDOT:PSS, caused by its PEDOT-rich and PSS-rich domains, induces many defects at the buried interface in PEDOT:PSS/perovskite, which limits device performance. Here, we present ionic exchange (IE) of PEDOT:PSS via a combination of methylamine iodide (MAI) and dimethyl sulfoxide (DMSO). Through surface analyses and density functional theory (DFT) simulations, we confirm that the IE process preferentially form PEDOT-I and MA-PSS and that PSS-rich domains bind to DMSO. Thus, the spatial separation of PEDOT:PSS is solved, and the exchanged MA + and I - ions serve as a bridge between PEDOT:PSS and the perovskite, leading to improved physical, chemical, and electrical properties of the buried interface. The Sn-Pb mixed perovskite solar cells using IE-PEDOT:PSS achieve an improved efficiency of 21.3% with an open-circuit voltage of 0.85 V and show better long-term stability. Additionally, IE-PEDOT:PSS works effectively in 2-terminal all-perovskite tandem devices, resulting in an improved efficiency of 23.5% and high reproducibility.

14 SOLAR ENERGY↗
DOE OSTI2020

Materials Data on SnPbS3 by Materials Project

PbSnS3 is Orthorhombic Perovskite-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Pb2+ is bonded in a 6-coordinate geometry to eight S2- atoms. There are a spread of Pb–S bond distances ranging from 2.77–3.70 Å. Sn4+ is bonded to six S2- atoms to form edge-sharing SnS6 octahedra. There are a spread of Sn–S bond distances ranging from 2.52–2.65 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to one Pb2+ and three equivalent Sn4+ atoms. In the second S2- site, S2- is bonded in a 2-coordinate geometry to three equivalent Pb2+ and two equivalent Sn4+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to four equivalent Pb2+ and one Sn4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnPbSe2 by Materials Project

PbSnSe2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pb2+ is bonded to six equivalent Se2- atoms to form PbSe6 octahedra that share corners with six equivalent SnSe6 octahedra, edges with six equivalent PbSe6 octahedra, and edges with six equivalent SnSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Pb–Se bond lengths are 3.10 Å. Sn2+ is bonded to six equivalent Se2- atoms to form SnSe6 octahedra that share corners with six equivalent PbSe6 octahedra, edges with six equivalent PbSe6 octahedra, and edges with six equivalent SnSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Sn–Se bond lengths are 3.04 Å. Se2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form a mixture of edge and corner-sharing SeSn3Pb3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnPbS2 by Materials Project

PbSnS2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pb2+ is bonded to six equivalent S2- atoms to form PbS6 octahedra that share corners with six equivalent SnS6 octahedra, edges with six equivalent PbS6 octahedra, and edges with six equivalent SnS6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Pb–S bond lengths are 3.00 Å. Sn2+ is bonded to six equivalent S2- atoms to form SnS6 octahedra that share corners with six equivalent PbS6 octahedra, edges with six equivalent PbS6 octahedra, and edges with six equivalent SnS6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Sn–S bond lengths are 2.93 Å. S2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form a mixture of edge and corner-sharing SSn3Pb3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnTe2Pb by Materials Project

PbSnTe2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pb2+ is bonded to six equivalent Te2- atoms to form PbTe6 octahedra that share corners with six equivalent SnTe6 octahedra, edges with six equivalent PbTe6 octahedra, and edges with six equivalent SnTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Pb–Te bond lengths are 3.28 Å. Sn2+ is bonded to six equivalent Te2- atoms to form SnTe6 octahedra that share corners with six equivalent PbTe6 octahedra, edges with six equivalent PbTe6 octahedra, and edges with six equivalent SnTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Sn–Te bond lengths are 3.21 Å. Te2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form a mixture of corner and edge-sharing TeSn3Pb3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
NASA NTRS2012

Volatile Siderophile Elements in Shergottites: Constraints on Core Formation and Magmatic Degassing

Volatile siderophile elements (e.g., As, Sb, Ge, Ga, In, Bi, Zn, Cd, Sn, Cu, Pb) can place constraints both on early differentiation as well as the origin of volatiles. This large group of elements has been used to constrain Earth accretion [1,2], and Earth-Moon geochemistry [3]. Application to Earth has been fostered by new experimental studies of these elements such as Ge, In, and Ga [4,5,6]. Application to Mars has been limited by the lack of data for many of these elements on martian meteorites. Many volatile elements are considered in the pioneering work by [7] but for only the small number of martian samples then available. We have made new measurements on a variety of martian meteorites in order to obtain more substantial datasets for these elements using the analytical approach of [8]. We use the new dataset, together with published data from the literature, to define martian mantle abundances of volatile siderophile elements. Then, we evaluate the possibility that these abundances could have been set by mid-mantle (14 GPa, 2100 C) metal-silicate equilibrium, as suggested by the moderately and slightly siderophile elements [9]. Finally, we examine the possibility that some elements were affected by volatility and magmatic degassing.

Righter, Kevin↗
DOE OSTI2020

Materials Data on SnP2PbO8 by Materials Project

PbSnP2O8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pb2+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.30 Å) and one longer (2.43 Å) Pb–O bond lengths. Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Sn–O bond distances ranging from 2.04–2.10 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SnO6 octahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SnO6 octahedra. The corner-sharing octahedra tilt angles range from 42–47°. There are a spread of P–O bond distances ranging from 1.52–1.57 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Pb2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Sn4+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sn4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Sn4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sn4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sn4+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sn4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Pb2+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Surface Sn(IV) Hydrolysis Improves Inorganic Sn–Pb Perovskite Solar Cells

Cesium tin-lead (Sn-Pb) perovskites are exceptional for their combined capabilities in unlocking ideal bandgaps for solar cells and mitigating the stability issue faced by their hybrid organic-inorganic counterparts. But the development of high-performance solar cells using these materials is retarded by their inherent high density of detrimental Sn(IV) defects. Herein, we demonstrate a sequential surface treatment method, which entails a Sn(II) halide treatment to displace the buried Sn(IV) ions underneath the film surface, followed by a H 2 O treatment to hydrolyze the displaced Sn(IV) ions. The surface treatment induces chemical and microstructural reconstructions that significantly improve the optoelectronic properties and stability of perovskites. As a result, a power conversion efficiency of 16.79% and a T 90 stability of 958 h are achieved, topping all previously reported performance parameters for inorganic Sn-Pb PSCs. This achievement further shortens the performance gap between all-inorganic and hybrid organic- inorganic Sn-Pb PSCs with sub-1.4 eV bandgaps.

14 SOLAR ENERGY↗
DOE OSTI2022

How additives for tin halide perovskites influence the Sn 4+ concentration

Tin halide perovskite (Sn-HPs) photovoltaics could potentially equal or exceed the performance of their more toxic Pb-based analogues if defect state densities, particularly originating from the presence of Sn 4+ , can be significantly decreased. Numerous additives are incorporated into Sn-HPs to minimize the amount of Sn 4+ , including SnF 2 , reducing agents such as hydrazine derivatives, and various antioxidants. However, despite the frequent use of additives to reduce Sn 4+ content, there is limited understanding of how they function and consequently limited guidance for the development of new additives. Herein, we use cyclic voltammetry to probe the redox behavior of SnI 2 , SnI 4 , Sn-HP precursor solutions, and 18 different additives. Through 119 Sn NMR measurements we show that hydrochloride containing additives undergo halide exchange with SnI 4 to form SnI x Cl y , which results in decreased Sn 4+ concentrations and less p-type character in the Sn-HP films. We find that the most effective additive at lowering the Sn 4+ content in FASnI 3 is not capable of reducing SnI 4 or forming SnI x Cl y , but rather it acts as a sacrificial and coordinating antioxidant. In general, when selecting additives for Sn-HPs it is important to account for the redox potential, coordination with Sn species, ability to react with oxygen, and the potential for halide exchange.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Synthesis, Structure, and Properties of the Complex Zintl Phase Eu 9 Zn 4.5 As 9 : A Candidate Topological Insulator and Thermoelectric Material

Reported are the synthesis and detailed analysis of the crystal and electronic structure of the novel Zintl phase Eu 9 Zn 4.5 As 9 . This material was identified in the densely populated Eu–Zn–As compositional space. For structure determination and for property measurements, suitable single crystals of this compound were grown from either Sn- or Pb-flux. Single-crystal X-ray diffraction methods indicate that Eu 9 Zn 4.5 As 9 crystallizes in the orthorhombic crystal system with the space group Pnma (a = 12.1953(7) Å, b = 4.3730(2) Å, c = 42.674(2) Å) and is formally isostructural to Ca 9 Mn 4+x Sb 9 , the less common “9–4–9” type. The structure is heavily disordered, with multiple partially occupied sites, yet, according to the Zintl-Klemm formalism, a charge-balanced composition (Eu 2+ ) 9 (Zn 2+ ) 4.5 (As 3− ) 9 is attained. Electronic structure calculations for a model, disorder-free structure indicate no energy gap between the valence and the conduction bands and suggest (semi)metallic behavior. Preliminary susceptibility measurements confirm the expected divalent nature of Eu 2+ ([Xe] 4 f 7 ground state).

Zintl phases↗
DOE OSTI2020

Materials Data on SnPb4Se5 by Materials Project

Pb4SnSe5 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to six Se2- atoms to form PbSe6 octahedra that share corners with three equivalent PbSe6 octahedra, corners with three equivalent SnSe6 octahedra, edges with three equivalent SnSe6 octahedra, and edges with nine PbSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are three shorter (3.09 Å) and three longer (3.12 Å) Pb–Se bond lengths. In the second Pb2+ site, Pb2+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing PbSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Pb–Se bond lengths are 3.09 Å. Sn2+ is bonded to six equivalent Se2- atoms to form SnSe6 octahedra that share corners with six equivalent PbSe6 octahedra, edges with six equivalent PbSe6 octahedra, and edges with six equivalent SnSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Sn–Se bond lengths are 3.05 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form a mixture of corner and edge-sharing SeSn3Pb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se2- site, Se2- is bonded to six equivalent Pb2+ atoms to form a mixture of corner and edge-sharing SePb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third Se2- site, Se2- is bonded to six Pb2+ atoms to form a mixture of corner and edge-sharing SePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnTePbSe by Materials Project

PbSnSeTe is Caswellsilverite-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Pb2+ is bonded to three equivalent Te2- and three equivalent Se2- atoms to form PbTe3Se3 octahedra that share corners with six equivalent SnTe3Se3 octahedra, edges with six equivalent PbTe3Se3 octahedra, and edges with six equivalent SnTe3Se3 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. All Pb–Te bond lengths are 3.26 Å. All Pb–Se bond lengths are 3.12 Å. Sn2+ is bonded to three equivalent Te2- and three equivalent Se2- atoms to form SnTe3Se3 octahedra that share corners with six equivalent PbTe3Se3 octahedra, edges with six equivalent PbTe3Se3 octahedra, and edges with six equivalent SnTe3Se3 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. All Sn–Te bond lengths are 3.19 Å. All Sn–Se bond lengths are 3.08 Å. Te2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form TeSn3Pb3 octahedra that share corners with six equivalent SeSn3Pb3 octahedra, edges with six equivalent TeSn3Pb3 octahedra, and edges with six equivalent SeSn3Pb3 octahedra. The corner-sharing octahedra tilt angles range from 3–4°. Se2- is bonded to three equivalent Pb2+ and three equivalent Sn2+ atoms to form SeSn3Pb3 octahedra that share corners with six equivalent TeSn3Pb3 octahedra, edges with six equivalent TeSn3Pb3 octahedra, and edges with six equivalent SeSn3Pb3 octahedra. The corner-sharing octahedra tilt angles range from 3–4°.

36 MATERIALS SCIENCE↗