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At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba4Ga5AgSe12 by Materials Project

Ba4AgGa5Se12 crystallizes in the tetragonal P-4 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Ag1+ and eight Se2- atoms. The Ba–Ag bond length is 3.43 Å. There are a spread of Ba–Se bond distances ranging from 3.36–3.79 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Ag1+ and eight Se2- atoms. The Ba–Ag bond length is 3.42 Å. There are a spread of Ba–Se bond distances ranging from 3.37–3.78 Å. Ag1+ is bonded to four Ba2+ and four Se2- atoms to form distorted AgBa4Se4 tetrahedra that share corners with four GaSe4 tetrahedra. All Ag–Se bond lengths are 2.65 Å. There are four inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share a cornercorner with one AgBa4Se4 tetrahedra and corners with three GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.42–2.46 Å. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share a cornercorner with one AgBa4Se4 tetrahedra and corners with three GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.42–2.47 Å. In the third Ga3+ site, Ga3+ is bonded to four equivalent Se2- atoms to form corner-sharing GaSe4 tetrahedra. All Ga–Se bond lengths are 2.45 Å. In the fourth Ga3+ site, Ga3+ is bonded to four equivalent Se2- atoms to form corner-sharing GaSe4 tetrahedra. All Ga–Se bond lengths are 2.45 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Ga3+ atoms. In the second Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Ga3+ atoms. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ga3+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ga3+ atoms. In the fifth Se2- site, Se2- is bonded in a 2-coordinate geometry to four Ba2+, one Ag1+, and one Ga3+ atom. In the sixth Se2- site, Se2- is bonded in a 2-coordinate geometry to four Ba2+, one Ag1+, and one Ga3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Investigation of Key Electronic States in Layered Mixed Chalcogenides With a d 0 Transition Metal as Li-Ion Cathodes

Lithium-rich transition metal chalcogenides are witnessing a revival as candidates for Li-ion cathode materials, spurred by the boost in their capacities from transcending conventional redox processes based on cationic states and tapping into additional chalcogenide states. A particularly striking case is Li 2 TiS 3-y Se y , which features a d 0 metal. While the end members are expectedly inactive, substantial capacities are measured when both Se and S are present. Using X-ray absorption spectroscopy, it is shown that the electronic structure of Li 2 TiS 3-y Se y is not a simple combination of the end members. The data confirm previous hypotheses that, in Li 2 TiS 2.4 Se 0.6 , this behavior is underpinned by concurrent and reversible redox of only S and Se, and identify key electronic states. Moreover, wavelet transforms of the extended X-ray absorption fine structure provide direct evidence of the formation of short Se–Se units upon charging. The study uncovers the underpinnings of this intriguing reactivity and highlights the richness of redox chemistry in complex solids.

25 ENERGY STORAGE↗
DOE OSTI2024

Investigation of Sub‐Bandgap Emission and Unexpected n‐Type Behavior in Undoped Polycrystalline CdSe x Te 1‐x

Abstract Se alloying has enabled significantly higher carrier lifetimes and photocurrents in CdTe solar cells, but these benefits can be highly dependent on CdSe x Te 1‐x processing. This work evaluates the optoelectronic, chemical, and electronic properties of thick (3 µm) undoped CdSe x Te 1‐x of uniform composition and varied processing conditions (CdSe x Te 1‐x evaporation rate, CdCl 2 anneal, Se content) chosen to reflect various standard device processing conditions. Sub‐bandgap defect emission is observed, which increased as Se content increased and with “GrV‐optimized CdCl 2 ” (i.e., CdCl 2 anneal conditions used for group‐V‐doped devices). Low carrier lifetime is found for GrV‐optimized CdCl 2 , slow CdSe x Te 1‐x deposition, and low‐Se films. Interestingly, all films (including CdTe control) exhibited n‐type behavior, where electron density increased with Se up to an estimated ≈10 17 cm −3 . This behavior appears to originate during the CdCl 2 anneal, possibly from Se diffusion leading to anion vacancy (e.g., V Se , V Te ) and Cl Te generation.

14 SOLAR ENERGY↗
DOE OSTI2020

Understanding Life History Diversity of a Wild Steelhead Population and Managing for Resiliency

Abstract Diversity in steelhead Oncorhynchus mykiss (anadromous Rainbow Trout) is often characterized by varying time spent in freshwater and saltwater environments. However, ontogenetic shifts are not often highlighted as an important diversity characteristic in salmonids. Larger water bodies can play a key role in population stability by buffering limited resources in smaller tributary systems. Based on freshwater and saltwater ages of adult steelhead in Fish Creek, Idaho, there were 12 different life history trajectories observed. Juvenile abundance varied from 12,083 (SE = 1,225.7) to 62,463 (SE = 1,753.8), with ages ranging from young of the year (age 0) to 4 years. Adult abundance fluctuated from 17 (SE < 0.1) to 499 (SE = 67.1), and total age of adults varied from 3 to 7 years. Diversity was most evident in juvenile movement and rearing strategies. We observed four types of movement and rearing pathways in which juveniles either directly migrated to the ocean from Fish Creek or resided for up to three winters in main-stem river habitat in the Clearwater River basin prior to ocean migration. Most juveniles emigrated in the fall at age 2, and most ocean-emigrating smolts were age 3. Subsequently, most juveniles resided for at least one additional winter period before ocean migration. Juvenile diversity was also reflected in adult ages; the mean proportion that spent 3 years in freshwater was 0.55 (SE = 0.03), and the mean proportion that spent 2 years in freshwater was 0.41 (SE = 0.03). Adult sex ratio was female biased (mean ± SE = 0.66 ± 0.02), with a higher proportion of females (0.89 ± 0.03) than males (0.65 ± 0.05) residing in the ocean for at least 2 years. Density-dependent mechanisms were evident in juvenile rearing habitat in Fish Creek for cohorts of high female abundance. Population productivity potentials can be met when tributary and main-stem rearing habitat can be utilized, and this will be essential in attaining recovery goals.

Dobos, Marika E.↗
DOE OSTI2019

Impact of regadenoson-induced myocardial creep on dynamic Rubidium-82 PET myocardial blood flow quantification

Background: Repositioning of the heart during myocardial perfusion imaging (MPI) using Rubidium-82 (Rb-82) PET may occur when using regadenoson. Our aim was to determine the prevalence and the effect of correcting for this myocardial creep on myocardial blood flow (MBF) quantification. Methods: We retrospectively included 119 consecutive patients who underwent dynamic rest- and regadenoson-induced stress MPI using Rb-82 PET. The presence of myocardial creep was visually assessed in the dynamic stress PET series by identifying differences between the automatically drawn myocardium contour and the activity. Uncorrected and corrected stress MBFs were compared for the three vascular territories (LAD, LCX, and RCA) and for the whole myocardium. Results: Myocardial creep was observed in 52% of the patients during stress. Mean MBF values decreased after correction in the RCA from 4.0 to 2.7 mL/min/g (P < 0.001), in the whole myocardium from 2.7 to 2.6 mL/min/g (P = 0.01), and increased in the LAD from 2.5 to 2.6 mL/min/g (P = 0.03) and remained comparable in the LCX (P = 0.3). Conclusions: Myocardial creep is a frequent phenomenon when performing regadenoson-induced stress Rb-82 PET and has a significant impact on MBF values, especially in the RCA territory. As this may hamper diagnostic accuracy, myocardial creep correction seems necessary for reliable quantification. [French] French Abstract: Contexte: Un repositionnement du cœur lors de l’imagerie de perfusion myocardique (MPI) à l’aide de la TEP au rubidium-82 (RB-82) peut survenir lors de l’utilisation du regadenoson. Notre objectif était de déterminer la prévalence et l’effet de la correction du fluage sur la quantification du débit sanguin myocardique (DSM). Méthodes: dans cette étude rétrospective, nous avons inclus 119 patients consécutifs ayant beneficié d’un examen au repos suivi d’un stress pharamacologique au régadénoson en utilisant le RB-82. La présence de fluage myocardique a été évaluée visuellement sur les images TEP de stress dynamique en utilisant les différences entre les contours automatiques et les images myocardiques. Les DSM de stress non corrigés et corrigés ont été comparés pour les trois territoires vasculaires (coronaire gauche-CG, la circonflexe-CX, et coronaire droite-CD) et pour l’ensemble du myocarde. Résultats: le fluage myocardique a été observé chez 52% des patients sur les examens de stress. Les valeurs moyennes de DSM ont diminué après correction dans le territoire de la CD de 4,0 à 2,7 mL/min/g (p < 0,001), dans le myocarde entier de 2,7 à 2,6 mL/min/g (p = 0,01) et augmenté dans le territoire de la CG de 2,5 à 2,6 mL/min/g (p = 0,03) et est resté comparable dans le territoire de la CX (p = 0,3). Conclusions: le fluage myocardique est un phénomène fréquent lors de l’exécution du stress phramacologique au régadénoson à l’aide du RB-82. Il a un impact significatif sur les valeurs de DSM, en particulier dans le territoire de la CD. La correction du fluage myocardique semble donc nécessaire pour une quantification fiable des flux coronariens. [Spanish] Spanish Abstract: Antecedentes: El movimiento del corazón durante la imagen de perfusión miocárdica usando Rubidio-82 (Rb-82) PET puede ocurrir cuando se usa regadenosón. Nuestro enfoque fue determinar la prevalencia y efecto de la corrección de este Artefacto de movimiento en la cuantificación del flujo sanguíneo miocárdico. Métodos: Se incluyeron de forma retrospectiva 119 pacientes que se realizaron estudio dinámico en reposo y estudio de perfusión miocárdica en estrés inducido por regadenosón usando Rb-82 PET. La presencia de el artefacto de movimiento fue evaluado visualmente en el estudio en serie de PET dinámico en estrés identificando las diferencias entre el contorno miocárdico dibujado automáticamente y la actividad. La perfusión miocárdica en estrés corregida y sin corregir se compararon para los tres territorios vasculares (Descendente Anterior, Circunfleja, Coronaria Derecha) y para todo el miocardio. Resultados: El artefacto de movimiento miocárdico se observo en un 52% de los pacientes durante el estrés. El promedio de los valores de flujo sanguíneo miocárdico disminuyen después de la corrección en la arteria coronaria derecha de 4.0 a 2.7 ml/min/g (p < 0.001), en todo el miocardio de 2.7 a 2.6 mL/min/g (p = 0.01) y un aumento en la arteria descendente anterior de 2.5 a 2.6 mL/min/g (p = 0.03) y se mantuvo comparable en la arteria circunfleja (p = 0.3). Conclusiones: El artefacto de movimiento miocárdico es un fenómeno frecuente cuando se realiza la prueba de estrés inducido con regadenosón Rb-82 PET y tiene un impacto significativo en los valores de flujo sanguíneo miocárdico, principalmente en el territorio de la coronaria derecha. Esto puede disminuir la precisión diagnostica, la corección del artefacto de movimiento es necesario para una cuantificación confiable. [Chinese] Chinese Abstract: 背景: 铷-82 (Rb-82) PET心肌灌注成像 (MPI) 过程在使用类伽腺苷时可能会发生心脏重定位。我们的目的是确定心肌蠕动 (myocardial creep) 校正对心肌血流灌注定量的影响及其普遍性。 方法: 我们连续回顾了119 名使用 Rb-82 PET 进行动态的静息与类伽腺苷负荷MPI的患者。通过识别自动绘制的心肌轮廓和心肌活动之间的差异, 在动态负荷 PET 检查中肉眼评估心肌蠕动的存在。分别在已校正和未校正的负荷 MBF上, 对三个血管区域 (LAD, LCX, RCA) 和整个心肌灌注情况进行比较。 结果: 负荷检查中, 52% 的患者观察到心肌蠕动。 RCA 校正后平均MBF值从4.0降至 2.7 mL / min / g (p <0.001), 整个心肌从 2.7降至 2.6 mL / min / g (p = 0.01) , LAD 从 2.5 升至 2.6mL / min / g (p = 0.03) 并且在LCX中保持不变 (p = 0.3) 。 结论: 类伽腺苷负荷 Rb-82 PET 检查中, 心肌蠕动是一种常见的现象, 并且对 MBF 值有显著影响, 特别在 RCA 区域。这可能妨碍诊断准确性, 因此心肌蠕动校正是准确定量的必要条件。.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Understanding metal propagation in solid electrolytes due to mixed ionic-electronic conduction

Metal penetration into a solid electrolyte (SE) is one of the critical problems impeding the practical application of solid-state batteries. In this study, we investigate the conditions under which electronic conductivity of the SE can lead to metal deposition and fracture within the SE. Three different stages for void filling (metal plating initiation, metal growth, and metal compression) in the SE are identified. We show that a micron-size isolated void in the SE near the anode can be quickly filled in by metal and fractured when the developed pressure in the void grows larger than the maximum pressure the SE material can sustain. We find that the anode voltage and applied current density play a significant role in determining the vulnerability to metal deposition. We discuss several strategies to prevent electronic conductivity-driven metal propagation in electrolytes that are not fully dense, including the densified layers between the anode and SE.

25 ENERGY STORAGE↗
DOE OSTI2020

Crystal Structure and Atomic Vacancy Optimized Thermoelectric Properties in Gadolinium Selenides

Thermoelectric materials enable the energy conversion of waste heat into electricity, helpful to relieve global energy crisis. Here, we report a systematic investigation on high-temperature thermoelectric gadolinium selenides, cubic Gd 3-x Se 4 (x = 0.16, 0.21 and 0.25) and orthorhombic Gd 2 Se 3-y (y = 0.02, 0.06 and 0.08). High energy synchrotron x-ray diffraction and total scattering have been used to investigate the crystallographic and local structures. Atomic-scale clusters of Gd vacancy in the cubic phase are observed by employing the reverse Monte Carlo simulation. For cubic Gd 3-x Se 4 , adjusting Gd vacancy triggers the effect of multiple conduction bands, confirmed by the increase in effective masses and theoretical calculations. A reasonable peak zT value of 0.27 is achieved at 850 K for Gd 3-x Se 4 (x = 0.16). On the other hand, tuning Se vacancy enables the optimization of electron concentration for the orthorhombic Gd 2 Se 3-y . More significantly, its low deformation potential (Ξ = 12eV) gives rise to enhanced electron mobility and higher peak zT value of 0.54 at 850 K for Gd 2 Se 3-y (y = 0.02). Intriguingly, a higher zT of 1.2 at 1200 K is reasonably predicted by quality factor analysis. Finally, this work extends the scope of high-temperature thermoelectric materials and facilitates the exploration of novel high-temperature thermoelectric materials

36 MATERIALS SCIENCE↗
DOE OSTI2020

Ultrafine Interwoven Dendritic Cu 2 Se/CuFeSe 2 Composites with Enhanced Thermoelectric Performance

As an effort to develop high-performance and stable copper chalcogenide thermoelectrics, several (1-x)Cu 2 Se/(x)CuFeSe 2 composites were successfully synthesized via a one-step solid-state transformation of CuSe 2 template. Uniform ultrafine dendritic structures consisting of interweaving Cu 2 Se and CuFeSe 2 nanofibers were observed in samples with low Fe content (0.05 ≤ x ≤ 0.1). Increasing the Fe content to x = 0.5 led to phase segregation into Cu 2 Se-rich region with embedded CuFeSe 2 fine structures interwoven with CuFeSe 2 -rich region containing Cu 2 Se nanofibers. The formation of such an entwined dendritic structure is believed to arise from the temperature-dependent solubility of CuFeSe 2 in the Cu 2 Se matrix. The dynamic dissolution of CuFeSe 2 into the Cu 2 Se at high temperatures leads to temperature-dependent doping of the Cu 2 Se matrix, enabling drastic enhancements of thermoelectric power factor at high temperatures. As a result, such a strategy is expected to be a powerful tool for properties modulation in thermoelectric materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Strong spin-dephasing in a topological insulator-paramagnet heterostructure

The interface between magnetic materials and topological insulators can drive the formation of exotic phases of matter and enable functionality through the manipulation of the strong spin polarized transport. Here, we report that the transport processes that rely on strong spin-momentum locking in the topological insulator Bi 2 Se 3 are completely suppressed by scattering at a heterointerface with the kagome-lattice paramagnet, Co 7 Se 8 . Bi 2 Se 3 –Co 7 Se 8 –Bi 2 Se 3 trilayer heterostructures were grown using molecular beam epitaxy, where magnetotransport measurements revealed a substantial suppression of the weak antilocalization effect for Co 7 Se 8 at thicknesses as thin as a monolayer, indicating a strong dephasing mechanism. Bi 2- x Co x Se 3 films, in which Co is in a non-magnetic 3 + state, show weak antilocalization that survives to higher than x = 0.4, which, in comparison with the heterostructures, suggests that the unordered moments of Co 2+ act as a far stronger dephasing element. This work highlights several important points regarding coherent transport processes involving spin-momentum locking in topological insulator interfaces and how magnetic materials can be integrated with topological materials to realize both exotic phases and novel device functionality.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Early crystallization of amorphous selenium under high pressure studied by synchrotron XRD method

Abstract The amorphous selenium (a-Se) was studied via x-ray diffraction (XRD) under pressures ranging from ambient pressure up to 30 GPa at room temperature to study its high-pressure behavior. Two compressional experiments on a-Se samples, with and without heat treatment, respectively, were conducted. Contrary to the previous reports that a-Se crystallized abruptly at around 12 GPa, in this work we report an early partially crystallized state at 4.9 GPa before completing the crystallization at around 9.5 GPa based on in-situ high pressure XRD measurements on the a-Se with 70 °C heat treatment. In comparison, crystallization pressure on another a-Se sample without thermal treatment history was observed to be 12.7 GPa, consistent with the previously reported crystallization pressure. Thus, it is proposed in this work that prior heat treatment of a-Se can result in an earlier crystallization under high pressure, which helps to understand the possible mechanism caused by the previous controversial reports on pressure induced crystallization behavior in a-Se.

Physics↗
DOE OSTI2020

Ion irradiation of iron chalcogenide superconducting films

Iron-chalcogenide FeSe x Te 1-x (Fe(Se,Te)) superconductors have attracted a great deal of interests in both fundamental physics and potential applications. While Majorana zero-modes hosted by the Fe(Se,Te) superconductors hold great promise for topological quantum computing, low-anisotropy and very high upper critical fields make Fe(Se,Te) an excellent candidate for high magnetic field and energy applications. Recently, we demonstrated a route for creating structural defects by ion irradiation in the FST films, leading to strong flux pinning. Ion irradiation into Fe(Se,Te) films significantly improved the critical current density J c over a wide field range and for all orientations with respect to magnetic field. In particular, a robust enhancement of critical temperature T c and J c was realized simultaneously in the Fe(Se,Te) film irradiated with proton. Here, we provide a review of the ion irradiated Fe(Se,Te) films, including the film growth and characteristics before and after irradiations, design of irradiation process for different ion energy and species with irradiation simulations and experimental setups that are scalable for long length Fe(Se,Te) coated conductors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on Cu8SiSe6 by Materials Project

Cu8SiSe6 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are five inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Cu–Se bond distances ranging from 2.37–3.05 Å. In the second Cu1+ site, Cu1+ is bonded in a distorted T-shaped geometry to three Se2- atoms. There are a spread of Cu–Se bond distances ranging from 2.42–2.60 Å. In the third Cu1+ site, Cu1+ is bonded to four Se2- atoms to form distorted CuSe4 tetrahedra that share corners with two equivalent SiSe4 tetrahedra and corners with six equivalent CuSe4 trigonal pyramids. There are a spread of Cu–Se bond distances ranging from 2.41–2.57 Å. In the fourth Cu1+ site, Cu1+ is bonded in a distorted trigonal planar geometry to three Se2- atoms. There are a spread of Cu–Se bond distances ranging from 2.45–2.55 Å. In the fifth Cu1+ site, Cu1+ is bonded to four Se2- atoms to form distorted CuSe4 trigonal pyramids that share corners with two equivalent SiSe4 tetrahedra, corners with three equivalent CuSe4 tetrahedra, a cornercorner with one CuSe4 trigonal pyramid, and an edgeedge with one CuSe4 trigonal pyramid. There are a spread of Cu–Se bond distances ranging from 2.43–2.73 Å. Si4+ is bonded to four Se2- atoms to form SiSe4 tetrahedra that share corners with two equivalent CuSe4 tetrahedra and corners with four equivalent CuSe4 trigonal pyramids. There are a spread of Si–Se bond distances ranging from 2.26–2.28 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to four Cu1+ and one Si4+ atom. In the second Se2- site, Se2- is bonded in a distorted trigonal bipyramidal geometry to five Cu1+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to eight Cu1+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted tetrahedral geometry to three Cu1+ and one Si4+ atom. In the fifth Se2- site, Se2- is bonded in a 6-coordinate geometry to five Cu1+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag2PSe3 by Materials Project

Ag2PSe3 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are four inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to one Ag1+ and four Se2- atoms. The Ag–Ag bond length is 3.10 Å. There are a spread of Ag–Se bond distances ranging from 2.70–2.78 Å. In the second Ag1+ site, Ag1+ is bonded in a 5-coordinate geometry to five Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.71–3.16 Å. In the third Ag1+ site, Ag1+ is bonded in a 8-coordinate geometry to two Ag1+ and six Se2- atoms. The Ag–Ag bond length is 3.00 Å. There are a spread of Ag–Se bond distances ranging from 2.66–3.58 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 5-coordinate geometry to one Ag1+ and five Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.68–3.29 Å. There are two inequivalent P4+ sites. In the first P4+ site, P4+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of P–Se bond distances ranging from 2.21–2.26 Å. In the second P4+ site, P4+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of P–Se bond distances ranging from 2.21–2.26 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 1-coordinate geometry to three Ag1+ and one P4+ atom. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ag1+ and one P4+ atom. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to four Ag1+ and one P4+ atom. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Ag1+ and one P4+ atom. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Ag1+ and one P4+ atom. In the sixth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Ag1+ and one P4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag8SnSe6 by Materials Project

Ag8SnSe6 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are five inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.68–2.76 Å. In the second Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to two Se2- atoms. There are one shorter (2.59 Å) and one longer (2.61 Å) Ag–Se bond lengths. In the third Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.57–3.66 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.71–2.79 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.69–2.94 Å. Sn4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are a spread of Sn–Se bond distances ranging from 2.55–2.57 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to five Ag1+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to eight Ag1+ atoms. In the third Se2- site, Se2- is bonded in a distorted trigonal pyramidal geometry to three Ag1+ and one Sn4+ atom. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ag1+ and one Sn4+ atom. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ag1+ and one Sn4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag8GeSe6 by Materials Project

Ag8GeSe6 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are five inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.62–2.88 Å. In the second Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.59–3.30 Å. In the third Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.69–2.76 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.65–2.99 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Ag–Se bond distances ranging from 2.67–2.77 Å. Ge4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are a spread of Ge–Se bond distances ranging from 2.38–2.41 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ag1+ and one Ge4+ atom. In the second Se2- site, Se2- is bonded in a distorted tetrahedral geometry to three Ag1+ and one Ge4+ atom. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to five Ag1+ and one Ge4+ atom. In the fourth Se2- site, Se2- is bonded in a 8-coordinate geometry to eight Ag1+ atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPSe6 by Materials Project

KPSe6 crystallizes in the orthorhombic Pca2_1 space group. The structure is two-dimensional and consists of one KPSe6 sheet oriented in the (1, 0, 0) direction. K1+ is bonded in a 8-coordinate geometry to eight Se1- atoms. There are a spread of K–Se bond distances ranging from 3.43–3.80 Å. P5+ is bonded in a tetrahedral geometry to four Se1- atoms. There are a spread of P–Se bond distances ranging from 2.18–2.33 Å. There are six inequivalent Se1- sites. In the first Se1- site, Se1- is bonded in a 1-coordinate geometry to two equivalent K1+ and one P5+ atom. In the second Se1- site, Se1- is bonded in a 4-coordinate geometry to two equivalent K1+ and two Se1- atoms. There are one shorter (2.42 Å) and one longer (2.46 Å) Se–Se bond lengths. In the third Se1- site, Se1- is bonded in a distorted single-bond geometry to one K1+ and one P5+ atom. In the fourth Se1- site, Se1- is bonded in a distorted single-bond geometry to one K1+, one P5+, and one Se1- atom. In the fifth Se1- site, Se1- is bonded in a distorted trigonal non-coplanar geometry to one K1+ and two Se1- atoms. The Se–Se bond length is 2.37 Å. In the sixth Se1- site, Se1- is bonded in a distorted single-bond geometry to one K1+, one P5+, and one Se1- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuSe2 by Materials Project

CuSe2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Cu3+ is bonded to six equivalent Se+1.50- atoms to form CuSe6 octahedra that share corners with eight equivalent CuSe6 octahedra, corners with six equivalent SeCu3Se tetrahedra, and edges with two equivalent CuSe6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are four shorter (2.57 Å) and two longer (2.58 Å) Cu–Se bond lengths. Se+1.50- is bonded to three equivalent Cu3+ and one Se+1.50- atom to form distorted SeCu3Se tetrahedra that share corners with three equivalent CuSe6 octahedra, corners with thirteen equivalent SeCu3Se tetrahedra, and an edgeedge with one SeCu3Se tetrahedra. The corner-sharing octahedra tilt angles range from 71–75°. The Se–Se bond length is 2.37 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2In12Se19 by Materials Project

K2In12Se19 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (3.51 Å) and three longer (3.60 Å) K–Se bond lengths. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to six Se2- atoms. There are three shorter (3.36 Å) and three longer (3.77 Å) K–Se bond lengths. There are four inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.59–2.75 Å. In the second In3+ site, In3+ is bonded to four Se2- atoms to form corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.58–2.74 Å. In the third In3+ site, In3+ is bonded to four Se2- atoms to form corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.56–2.70 Å. In the fourth In3+ site, In3+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.62–2.69 Å. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted trigonal planar geometry to one K1+ and two In3+ atoms. In the second Se2- site, Se2- is bonded to one K1+ and three In3+ atoms to form a mixture of distorted edge and corner-sharing SeKIn3 trigonal pyramids. In the third Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three In3+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent In3+ atoms. In the fifth Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three In3+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to one K1+ and two equivalent In3+ atoms. In the seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗