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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Restricted Rotational Flexibility of the C5α-Methyl-Substituted Carbapenem NA-1-157 Leads to Potent Inhibition of the GES-5 Carbapenemase

Carbapenem antibiotics are used as a last-resort treatment for infections caused by multidrug-resistant bacteria. The wide spread of carbapenemases in Gram-negative bacteria has severely compromised the utility of these drugs and represents a serious public health threat. To combat carbapenemase-mediated resistance, new antimicrobials and inhibitors of these enzymes are urgently needed. Here, we describe the interaction of the atypically C5α-methyl-substituted carbapenem, NA-1-157, with the GES-5 carbapenemase. MICs of this compound against Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii producing the enzyme were reduced 4–16-fold when compared to MICs of the commercial carbapenems, reaching clinically sensitive breakpoints. When NA-1-157 was combined with meropenem, a strong synergistic effect was observed. Kinetic and ESI-LC/MS studies demonstrated that NA-1-157 is a potent inhibitor of GES-5, with a high inactivation efficiency of (2.9 ± 0.9) × 105 M –1 s –1 . Acylation of GES-5 by NA-1-157 was biphasic, with the fast phase completing within seconds, and the slow phase taking several hours and likely proceeding through a reversible tetrahedral intermediate. Deacylation was extremely slow (k 3 = (2.4 ± 0.3) × 10 –7 s –1 ), resulting in a residence time of 48 ± 6 days. MD simulation of the GES-5-meropenem and GES-5-NA-1-157 acyl-enzyme complexes revealed that the C5α-methyl group in NA-1- 157 sterically restricts rotation of the 6α-hydroxyethyl group preventing ingress of the deacylating water into the vicinity of the scissile bond of the acyl-enzyme intermediate. Furthermore, these data demonstrate that NA-1-157 is a potent irreversible inhibitor of the GES-5 carbapenemase.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Unveiling the structure and electronic characteristics of amorphous GeS for high performance threshold switching

Ovonic threshold switching selectors are widely studied owing to the essential application in high density phase-change memory. Amorphous GeS is proposed as a potential candidate for the excellent performance. However, the knowledge of amorphous GeS is still insufficient up to date. Here, we have studied the structure and electronic characteristics of GeS in the amorphization process, by using ab initio molecular dynamics simulations. The results indicate that the amorphous GeS is mainly made up of Ge–S bonds. The Ge- and S-centered clusters are dominantly in the form of octahedral structures in liquid GeS. Furthermore, during the amorphization process, most of Ge-centered clusters become highly coordinated octahedrons while a small number of Ge-centered clusters change to tetrahedrons, and the S-centered clusters deviate from the octahedral structure gradually. In addition, the large bandgap and the relatively small mid-gap states in amorphous GeS lead to a high switching voltage.

42 ENGINEERING↗
DOE OSTI2023

Li 2 GeS 3 : Lithium Ionic Conductor with an Unprecedented Structural Type

Lithium-ion batteries (LIBs) are widely used in electric vehicles, mobile electronic devices, and large-scale stationary energy storage systems. However, their liquid electrolytes present significant safety concerns due to their inherent flammability. To address this, the focus has shifted toward all-solid-state batteries (ASSBs) utilizing inorganic solid electrolytes that promise enhanced safety. In this work, we report the discovery of a new crystal structural type of Li-ion conductor, Li 2 GeS 3 , with a unique structure, synthesized by a solid-state reaction from Li 2 S and GeS 2 . It was first reported in 2000 with an orthorhombic unit cell, but its detailed crystal structure remains veiled. Here, we have unveiled its structure for the first time, employing an ab initio structure determination technique from powder X-ray and time-of-flight neutron diffraction data. The compound has an unprecedented crystal structural type with a hexagonal $P6_1$ symmetry and a unit cell of α = 6.79364(4) Å and c = 17.90724(14) Å. Its structure is comprised of a distorted hexagonal close-packed arrangement of sulfur anions with three asymmetric metal atoms: Li1, Li2, and Ge are in tetrahedral cavities surrounded by sulfur atoms. The ionic conductivity of Li 2 GeS 3 was measured to be 1.63 × 10 –8 S cm –1 at 303 K and 2.45 × 10 –7 S cm –1 at 383 K. Bond valence energy landscape calculations revealed three-dimensional lithium diffusion pathways within the structure. This novel crystal structure in Li 2 GeS 3 holds the potential for developing high-performance ionic conductors through suitable chemical substitution and offers valuable insights into designing new ionic conductors for ASSBs.

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

Tailoring electrophotonic capabilities of atomically thin GeS through controlled organometallic intercalation

The unique structure of van der Waals materials facilitates a robust mechanism for precise control of physical properties. In this study, we present a comprehensive analysis based on the intercalation of organometallics to modulate the optoelectronic behavior of two-dimensional germanium sulfide (GeS). Advanced computational exploration reveals significant and tunable features in the intercalated material. Additionally, the weak chemical interactions between organometallics and GeS support the electric-field-mediated drift and charge–discharge processes in intercalants. Controlling the concentration of organometallics in this manner enables the dynamic emergence of novel characteristics post-intercalation. These include flatbands near the Fermi level, significant enhancement of carrier mobility, and a magnetic ground state that is atypical for pristine GeS. Our findings demonstrate that organometallic intercalation offers a powerful strategy for tailoring the optoelectronic and magnetic characteristics of GeS, paving the way for harnessing emerging features for applications in next-generation devices.

Physics↗
DOE OSTI2022

Valence Disproportionation of GeS in the PbS Matrix Forms Pb 5 Ge 5 S 12 Inclusions with Conduction Band Alignment Leading to High n-Type Thermoelectric Performance

Converting waste heat into useful electricity using solid-state thermoelectrics has a potential for enormous global energy savings. Lead chalcogenides are among the most prominent thermoelectric materials, whose performance decreases with an increase in chalcogen amounts (e.g., PbTe>PbSe>PbS). Herein, we demonstrate the simultaneous optimization of the electrical and thermal transport properties of PbS-based compounds by alloying with GeS. The addition of GeS triggers a complex cascade of beneficial events as follows: Ge 2+ substitution in Pb 2+ and discordant off-center behavior; formation of Pb 5 Ge 5 S 12 as stable second phase inclusions through valence disproportionation of Ge 2+ to Ge0 and Ge 4+ . PbS and Pb 5 Ge 5 S 12 exhibit good conduction band energy alignment that preserves the high electron mobility; the formation of Pb 5 Ge 5 S 12 increases the electron carrier concentration by introducing S vacancies. Sb doping as the electron donor produces a large power factor and low lattice thermal conductivity (κ lat ) of ~0.61 Wm -1 K -1 . The highest performance was obtained for the 14% GeS-alloyed samples, which exhibited an increased room temperature electron mobility of ~121 cm 2 V -1 s -1 for 3 × 10 19 cm -3 carrier density, and a ZT, of 1.32 at 923 K. This is ~ 55% greater that the corresponding Sb-doped PbS sample and is one of the highest reported for the n-type PbS system. Moreover, the average ZT (ZT avg ) of ~0.76 from 400 to 923 K is the highest for PbS-based systems.

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

Materials Data on GeS by Materials Project

GeS crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of two GeS sheets oriented in the (0, 1, 0) direction. Ge2+ is bonded to five equivalent S2- atoms to form a mixture of corner and edge-sharing GeS5 square pyramids. There are one shorter (2.38 Å) and four longer (2.75 Å) Ge–S bond lengths. S2- is bonded to five equivalent Ge2+ atoms to form a mixture of corner and edge-sharing SGe5 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeS by Materials Project

GeS is Hittorf-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two GeS sheets oriented in the (0, 0, 1) direction. Ge2+ is bonded in a distorted T-shaped geometry to three equivalent S2- atoms. All Ge–S bond lengths are 2.46 Å. S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Utah FORGE: GES Well 16A(78)-32 and Well 16B(78)-32 Stimulation Seismic Event Catalogs

This dataset contains seismic event catalogs from the hydraulic stimulation of wells 16A(78)-32 and 16B(78)-32 at the Utah FORGE site in April 2024. The data was collected by Geo Energy Suisse (GES) using a variety of seismic monitoring technologies, including 3-component (3C) geophones and distributed acoustic sensing (DAS) systems. These technologies were deployed across several locations, including wells 16A, 16B, and Delano-1, with sensor arrays at multiple depths to capture microseismic activity during the stimulations. The catalogs provide both real-time and manually checked seismic event locations, with detailed parameters such as trigger conditions, velocity models, and data acquisition settings. The dataset includes information on the stimulation stages, event rates, and hydraulic injection conditions for each well, with a report detailing the data acquisition configuration and seismic event location methodologies. Users will need to reference the included report for a complete understanding of the sensor network, data processing techniques, and accuracy considerations.

15 GEOTHERMAL ENERGY↗
DOE OSTI2020

Materials Data on Co2(GeS)3 by Materials Project

Co2(GeS)3 is Hausmannite-derived structured and crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are four inequivalent Co sites. In the first Co site, Co is bonded to three equivalent Ge and three equivalent S atoms to form CoGe3S3 octahedra that share corners with six equivalent CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. All Co–Ge bond lengths are 2.33 Å. All Co–S bond lengths are 2.24 Å. In the second Co site, Co is bonded to three equivalent Ge and three equivalent S atoms to form CoGe3S3 octahedra that share corners with six equivalent CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–58°. All Co–Ge bond lengths are 2.33 Å. All Co–S bond lengths are 2.24 Å. In the third Co site, Co is bonded to three Ge and three S atoms to form CoGe3S3 octahedra that share corners with six CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are two shorter (2.32 Å) and one longer (2.34 Å) Co–Ge bond lengths. There are a spread of Co–S bond distances ranging from 2.24–2.27 Å. In the fourth Co site, Co is bonded to three Ge and three S atoms to form CoGe3S3 octahedra that share corners with six CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are two shorter (2.32 Å) and one longer (2.34 Å) Co–Ge bond lengths. There are one shorter (2.24 Å) and two longer (2.26 Å) Co–S bond lengths. There are four inequivalent Ge sites. In the first Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–71°. There are one shorter (2.42 Å) and one longer (2.58 Å) Ge–S bond lengths. In the second Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 69–73°. There are one shorter (2.41 Å) and one longer (2.58 Å) Ge–S bond lengths. In the third Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 69–73°. There are one shorter (2.42 Å) and one longer (2.58 Å) Ge–S bond lengths. In the fourth Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–72°. There are one shorter (2.42 Å) and one longer (2.60 Å) Ge–S bond lengths. There are four inequivalent S sites. In the first S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–75°. In the second S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–75°. In the third S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 67–73°. In the fourth S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 67–73°.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Ultrafast Optomechanical Strain in Layered GeS

Strong coupling between light and mechanical strain forms the foundation for next-generation optical micro- and nano-electromechanical systems. Such optomechanical responses in two-dimensional materials present novel types of functionalities arising from the weak van der Waals bond between atomic layers. In this paper, by using structure-sensitive megaelectronvolt ultrafast electron diffraction, we report the experimental observation of optically driven ultrafast in-plane strain in the layered group IV monochalcogenide germanium sulfide (GeS). Surprisingly, the photoinduced structural deformation exhibits strain amplitudes of order 0.1% with a 10 ps fast response time and a significant in-plane anisotropy between zigzag and armchair crystallographic directions. Rather than arising due to heating, experimental and theoretical investigations suggest deformation potentials caused by electronic density redistribution and converse piezoelectric effects generated by photoinduced electric fields are the dominant contributors to the observed dynamic anisotropic strains. Our observations define new avenues for ultrafast optomechanical control and strain engineering within functional devices.

2D materials↗
DOE OSTI2025

Coherent Spins in van der Waals Semiconductor GeS 2 at Ambient Conditions

Optically active spin defects in van der Waals (vdW) materials have emerged as versatile quantum sensors, enabling applications for a wide range of quantum phenomena in condensed matter systems. Their ease of exfoliation and compatibility with device integration make them promising candidates for future quantum technologies. Here we report the observation and room-temperature coherent control of ensemble spin defects in the high-temperature crystalline phase of germanium disulfide (β-GeS 2 ), a two-dimensional (2D) semiconductor with low nuclear spin density. The defects exhibit spin-1/2 behavior, and their dynamics can be explained by a weakly coupled spin-pair model. We implement dynamical decoupling techniques to extend the coherence time (T 2 ) by a factor of 20. Finally, we use density functional theory (DFT) calculations to estimate the structures and spin densities of two possible spin defect candidates. This work will help to expand the field of quantum sensing with spin defects in 2D materials.

2D materials↗
DOE OSTI2020

Lateral Heterostructures of Multilayer GeS and SnS van der Waals Crystals

Engineered heterostructures derive distinct properties from materials integration and interface formation. Two-dimensional crystals have been combined to form vertical stacks and lateral heterostuctures with covalent line interfaces. While thicker vertical stacks have been realized, lateral heterostructures from multilayer van der Waals crystals, which could bring the benefits of high-quality interfaces to bulk-like layered materials, have remained much less explored. In this work, we demonstrate the integration of anisotropic layered Sn and Ge monosulfides into complex heterostructures with seamless lateral interfaces and tunable vertical design using a two-step growth process. The anisotropic lattice mismatch at the lateral interfaces between GeS and SnS is relaxed via dislocations and interfacial alloying. Nanoscale optoelectronic measurements by cathodoluminescence spectroscopy show the characteristic light emission of joined high-quality van der Waals crystals. Spectroscopy across the lateral interface indicates valley-selective luminescence in the bulk SnS component that arises due to anisotropic electron transfer across the interface. The results demonstrate the ability to realize high-quality lateral heterostructures of multilayer van der Waals crystals for diverse applications, e.g., in optoelectronics or valleytronics.

36 MATERIALS SCIENCE↗
DOE OSTI2020

BaGa{sub 2}GeS{sub 6} and BaGa{sub 2}GeSe{sub 6} crystals for nonlinear optical frequency conversion

We analyse the functional capabilities of new crystals, BaGa{sub 2}GeS{sub 6} (BGGS) and BaGa{sub 2}GeSe{sub 6} (BGGSe), which are used for nonlinear optical frequency conversion in their transparency range. The wavelengths at which maximum conversion efficiencies can be obtained and the tuning range for difference-frequency generation are found. It is shown that there are wavelength combinations at which the effective nonlinearity coefficient varies only slightly in a wide frequency band. (nonlinear optical phenomena)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Value of Geothermal Energy Storage for Supply-Side and Demand-Side Applications

This report presents the results of a study examining the value potential for geothermal energy storage (GES), a long-duration energy storage resource that stores thermal and/or geomechanical energy in the subsurface. GES could benefit the overall U.S. power system by temporally shifting electricity generation (supply-side) or meeting building heating and cooling load (demand-side). This report analyzes supply-side and demand-side opportunities independently because of differences in applications and models. Currently there is significant uncertainty about the development costs for GES, with only a limited number of demonstration plants for electric energy storage and building heating and cooling storage developments. In this report, we estimate the value of supply-side and demand-side GES to the bulk power system in the contiguous United States. Because of the significant uncertainty about GES development costs, this analysis does not consider GES deployment costs but instead focuses on the value of GES to the U.S. electricity system. The estimated values of GES provide reference points for economically competitive commercial cost targets. Supply-side GES is modeled as part of an enhanced geothermal system (EGS) generation plant in NREL's Regional Energy Deployment System (ReEDS) capacity expansion model (Ho et al. 2021). In contrast to conventional geothermal plants, which generate constant power, EGS plants have unique features that may allow for in-reservoir energy storage for flexible generation. Demand-side GES for heating and cooling, including seasonal hot and cold storage and short-duration heat pump storage, is incorporated into a price-taker model using Cambium electricity marginal cost projections. To establish an upper bound for the value of GES, analysis focused on favorable scenarios for storage with high generation from zero marginal cost, variable renewable energy resources. High penetrations of variable renewable energy generation can increase hourly electricity price variability, which increases the value of temporal energy arbitrage for storage technologies like GES.

15 GEOTHERMAL ENERGY↗