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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Multimodal Instrument Platform for High-Pressure MAS-NMR and IR Spectroscopic Interrogation

This project developed and tested a high-pressure (HP) flow-through instrument platform that combines HP- magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy for interrogating reactivity at interfaces between solid materials and HP fluids with HP- infrared (IR) spectroscopy for measuring fluid composition. Solid-fluid interfacial reactivity is usually dependent on concentrations of species within the fluid; thus, knowledge of the fluid composition measured by IR is critical to understanding solid-fluid interfacial reactivity probed by NMR. This new system adds to PNNL’s core capabilities in Chemical and Material Sciences to support fundamental programs in catalysis, interfacial molecular science, and geosciences, as well as in Earth and Biological Sciences to support energy production and storage, efforts to mitigate the impacts energy production systems, attenuation of contaminant plumes, and design of subsurface engineered systems for energy production and waste disposal.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Understanding the optoelectronic properties of doped 2D organic-inorganic halide perovskite quantum wells: towards efficient quantum well IR photodetectors

Metal halide perovskite (MHP) multiple quantum wells which consist of multilayers of alternate organic and inorganic layers exhibit large exciton binding energies due to the dielectric confinement between the inorganic and organic layers. These naturally formed multiple quantum wells have strong spin-orbit coupling (SOC) due to the presence of heavy elements in their crystal structures. Although the fundamental properties of 2D MHPs are far from being entirely understood, it is widely accepted that their band edge absorption coefficient results from strong exciton interactions. However, studies demonstrating how different exciton interactions and doping effects influence electronic traps and disorder on the band edge absorption coefficient of 2D MHPs have not been demonstrated. Understanding these interactions in MHPs will allow us to access low energy optical transitions for the fabrication of solution processable short-to-mid-wavelength IR photodetectors (1 – 8 μm). Moreover, upon doping, it is possible to move the Fermi energy into the conduction band (CB) to favorably promote the transport of charges in a working device. Herein, we study the development of 2D MHPs having strong SOC, high carrier mobility, and tunable quantum well structures. Our studies shed light on the design and modulation of fundamental physical phenomena by carefully elucidating the role of dopants (n-type and p-type), exciton heterogeneity, orientation, structure, and bias stress effects on the performance of MHPs as potential IR photodetectors.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Understanding the optoelectronic properties of doped 2D organic-inorganic halide perovskite quantum wells: towards efficient ultrafast quantum well IR photodetectors

This project, titled “Understanding the optoelectronic properties of doped 2D organic-inorganic halide perovskite quantum wells: towards efficient quantum well IR photodetectors”, was funded by the U.S. Department of Energy to explore a new class of materials that could make future light-sensing technologies, such as infrared (IR) cameras and detectors more efficient, affordable, and widely available. The research focused on special layered materials called 2D halide perovskites, which are made up of alternating organic and inorganic layers only a few atoms thick. These materials can be tuned at the atomic level to absorb and emit light in precise ways, making them very attractive for use in optoelectronic devices. The main goal of the project was to understand how these perovskite materials absorb light and move electrical charges at very small scales. However, this is not an easy task. These materials often contain a mixture of different structures in the same film, and traditional tools like regular absorption or photoluminescence spectroscopy are not good at telling those structures apart. To solve this, the research team, led by Professor Luisa Whittaker-Brooks at the University of Utah developed a powerful method called electroabsorption spectroscopy. This technique uses electric fields to highlight the unique “fingerprints” of different excitons, which are tiny packets of energy formed when light hits the material. By using this method, the team could separate overlapping signals and learn exactly how the materials respond to light under different conditions, including changes in temperature, thickness, and chemical makeup.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Autonomous Infrared and Small (Wide) Angle X-Ray Scattering (IR-S(W)AXS) Capability

Thin water films are 2-D, nanoconfined layers that form on solid surfaces exposed to humid atmospheres—environments ubiquitous across catalysis, corrosion science, soil science, and subsurface geochemistry. At relative humidity (RH) values below saturation, these films are Å–nm thick and exhibit properties that differ sharply from bulk water, including disrupted H-bonding and impeded mass transport. Owing to their high surface-to-volume ratio, dissolution of the solid can rapidly drive strong supersaturation with respect to secondary phases. Reactivity in thin water films is highly sensitive to film thickness, and critically, thickness evolves during reaction because the hygroscopicity of the interfacial system changes as ions accumulate or diminish in the film and as reaction products transform. To accurately probe and control these dynamics, a capability is needed that can measure and automatically maintain a constant water-film thickness while simultaneously monitoring solid dissolution, nucleation, and growth. This project developed an autonomous Infrared/Small Angle X-ray Scattering-Wide Angle X-ray Scattering (IR/(W)SAXS) for investigating reactivity in thin water films on solid surfaces exposed to humidified gases. The capability consists of an IR spectrometer, a (W)SAXS instrument, and a mass flow controller system for generating variably humidified gas flows to a custom reaction cell. Progress on each of the major components of the capability are detailed below.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

SABRE Ir-IMes Catalysis for the Masses

The Signal Amplification By Reversible Exchange (SABRE) technique provides enhancement of Nuclear Magnetic Resonance (NMR) signals up to several orders of magnitude using chemical exchange of a substrate and parahydrogen on an iridium complex. Therefore, the availability of such a catalytic complex to a broader community is an absolutely vital step for dissemination of the groundbreaking SABRE methodology. The most common SABRE catalyst, which is activated in situ, is based on Ir-IMes system (IMes = 1,3-Bis(2,4,6-trimethylphenyl)imidazol-2-ylidene). Earlier approaches for the synthesis of this catalyst often relied on specialized equipment and were limited to a comparatively small scale. This, in turn, increased the barrier of entry for new scientists to the area of SABRE hyperpolarization. Here, we present a robust, inexpensive, and easy to reproduce synthetic procedure for the preparation of this SABRE catalyst, which does not require specialized inert atmosphere equipment like a glove box or Schlenk line. The synthesis was validated on the scale of several grams vs. tens of milligrams scale in the reported approaches. The resulting SABRE catalyst, [Ir(IMes)(COD)Cl], was activated in situ and further evaluated in hyperpolarization experiments resulting in signal enhancements comparable to (or higher than) those for the catalyst prepared using Schlenk line equipment.

Biochemistry & Molecular Biology↗
DOE OSTI2020

Polarization Dependent Excitation and High Harmonic Generation from Intense Mid-IR Laser Pulses in ZnO

The generation of high order harmonics from femtosecond mid-IR laser pulses in ZnO has shown great potential to reveal new insight into the ultrafast electron dynamics on a few femtosecond timescale. In this work we report on the experimental investigation of photoluminescence and high-order harmonic generation (HHG) in a ZnO single crystal and polycrystalline thin film irradiated with intense femtosecond mid-IR laser pulses. The ellipticity dependence of the HHG process is experimentally studied up to the 17th harmonic order for various driving laser wavelengths in the spectral range 3–4 µm. Interband Zener tunneling is found to exhibit a significant excitation efficiency drop for circularly polarized strong-field pump pulses. For higher harmonics with energies larger than the bandgap, the measured ellipticity dependence can be quantitatively described by numerical simulations based on the density matrix equations. The ellipticity dependence of the below and above ZnO band gap harmonics as a function of the laser wavelength provides an efficient method for distinguishing the dominant HHG mechanism for different harmonic orders.

tunneling excitation↗
DOE OSTI2020

Development of the Intelligent, Preventive Infrared (IR) Inspection System Housed in Hybrid Robotic Platforms

Robots and robotic systems that are designed for inspection, environmental study, and health and safety aid are becoming an increasing necessity. However, there is a number of challenges that accompany robots that are designed for these specific applications. These challenges include: navigating compact, enclosed spaces, travelling over multiple terrains and large obstacles, using the proper sensing and detection methods to assess an environment, and the use of lightweight and durable materials. The robotic platforms currently in development look at all of these challenges and attempt to overcome them. These designs specific use of hybrid robotic platforms, or platform that utilizes soft and rigid materials, allows for a more flexible platform and makes environments more navigable. To further improve the navigation of the platforms and environmental assessment, a novel infrared detection system is housed in the platforms to create a robot that can be used for the applications listed above and more. Objectives: Further develop two types of robotic platforms that utilize additive manufacturing, soft materials, and rigid materials. Continue the development of an intelligent and inhibitory infrared detection system based on an artificial intelligence (AI) algorithm. Continued study and fabrication of active soft materials designed for both sensing and actuation in hybrid robotic systems. Improve additive manufacturing fabrication to design rigid and semi-rigid components for hybrid robotic platforms. Transformable Wheel Robotic Platform: The chassis, wheels, tires and inspection system housing use different additive manufacturing techniques for fabrication. Continued work with additive manufacturing has lead to studies in metal-based printing and modular design and manufacturing. The new platform design with integrated electrical component printed. This will allow integration of the sensor housing onto the platform. Electrical components are being tested for battery life and performance. To improve this performance, such as integration of Lithium Polymer (LiPo) batteries. Snake Robotic Platform: The main focus of the development has centered around liquid-based soft actuators. That act on the principles of electrostatic and hydraulic actuation. A liquid dielectric sits between two compliant electrodes, contained by a flexible polymer shell. The electrodes and film gradually collapse toward each other from one corner of the electrode to the other. When the electrodes and film close together, a majority of the fluid is pushed into the area not covered by an electrode. A thin layer of the liquid dielectric remains between the electrode. The actuators will be stacked to cause large displacement, and move the linkages. The chassis of this platform uses purely additively manufactured linkages. Intelligent, Preventive IR Inspection System: Development of the AI for the system has lead to using a Scikit-Learn which assists in creating predictive models based on Regression, clustering, classification etc. To improve the infrared thermometry for low emissivity sources, work on the fabrication of a tandem photoconductive infrared thermometer was a main focus. Distance-Voltage-Temperature response data has been collected in the range of 7 cm - 100 cm and 200-400 deg. C. Modifications were made to the existing test bench to have a better control over the data. Automated data collection was realized using a Python code and an Arduino controlled stepper motor to increase the sample rate. A protective enclosure has been built around the setup to minimize the effect of the environment on the measurements. To better predict temperature, different AI models are being optimized. The regression model, LARS showed a high accuracy but had convergence issues and only works for the current test set-up. Results: The Transformable Wheel Robot has developed into a more flexible and modular platform. With the improvements to the current work, effort on the tire or soft gripper design been a large focus. The soft grippers will be interchange able to allow for increased performance in identified terrain types. The development of the liquid-based actuators allows the snake robotic platform to achieve the goals of being flexible and able to navigate confined spaces. However, there is room for improvement. Optimization work is currently being done in COMSOL Multiphysics. With the current IR system set-up the LARS model perfectly predicts the data; however, considering the mobility aspect of the project other models will allow for an optimized system. Testing of other model types is currently being done.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on Ir(SeBr3)3 by Materials Project

IrSe3Br8Br crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four hydrobromic acid molecules and four IrSe3Br8 clusters. In each IrSe3Br8 cluster, Ir3+ is bonded in a T-shaped geometry to three Se2- atoms. There are a spread of Ir–Se bond distances ranging from 2.37–2.49 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ir3+ and four Br+0.33+ atoms. There are a spread of Se–Br bond distances ranging from 2.39–3.03 Å. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.36 Å) and one longer (2.42 Å) Se–Br bond lengths. In the third Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.36 Å) and one longer (2.38 Å) Se–Br bond lengths. There are eight inequivalent Br+0.33+ sites. In the first Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the second Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the third Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fourth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fifth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the sixth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the seventh Br+0.33+ site, Br+0.33+ is bonded in a distorted single-bond geometry to one Se2- atom. In the eighth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(N2Cl3)2 by Materials Project

IrCl6(N2)2 is Fluorite structured and crystallizes in the tetragonal I4mm space group. The structure is zero-dimensional and consists of four nitrogen molecules and two IrCl6 clusters. In each IrCl6 cluster, Ir4+ is bonded in an octahedral geometry to six Cl1- atoms. There are one shorter (2.27 Å) and five longer (2.31 Å) Ir–Cl bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(SeBr3)3 by Materials Project

IrSe3Br7(Br)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four hydrobromic acid molecules and two IrSe3Br7 clusters. In each IrSe3Br7 cluster, Ir3+ is bonded in a distorted T-shaped geometry to three Se2- atoms. There are a spread of Ir–Se bond distances ranging from 2.40–2.44 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.38 Å) and one longer (2.40 Å) Se–Br bond lengths. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.38 Å) and one longer (2.42 Å) Se–Br bond lengths. In the third Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to one Ir3+ and three Br+0.33+ atoms. There are a spread of Se–Br bond distances ranging from 2.39–3.00 Å. There are seven inequivalent Br+0.33+ sites. In the first Br+0.33+ site, Br+0.33+ is bonded in a distorted single-bond geometry to one Se2- atom. In the second Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the third Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fourth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fifth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the sixth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the seventh Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(Br3O)2 by Materials Project

IrBr6O2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight water molecules and four IrBr6 clusters. In each IrBr6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Br atoms. All Ir–Br bond lengths are 2.43 Å. Br is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(Br3N)2 by Materials Project

IrBr6N2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight ammonia molecules and four IrBr6 clusters. In each IrBr6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Br1- atoms. All Ir–Br bond lengths are 2.46 Å. Br1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(NCl3)2 by Materials Project

IrCl6N2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight ammonia molecules and four IrCl6 clusters. In each IrCl6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Cl1- atoms. All Ir–Cl bond lengths are 2.30 Å. Cl1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

In situ X-ray and IR probes relevant to Earth science at the Advanced Light Source at Lawrence Berkeley Laboratory

Access to synchrotron X-ray facilities has become an important aspect for many disciplines in experimental Earth science. This is especially important for studies that rely on probing samples in situ under natural conditions different from the ones found at the surface of the Earth. The non-ambient condition Earth science program at the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, offers a variety of tools utilizing the infra-red and hard X-ray spectrum that allow Earth scientists to probe Earth and environmental materials at variable conditions of pressure, stress, temperature, atmospheric composition, and humidity. These facilities are important tools for the user community in that they offer not only considerable capacity (non-ambient condition diffraction) but also complementary (IR spectroscopy, microtomography), and in some cases unique (Laue microdiffraction) instruments. The availability of the ALS’ in situ probes to the Earth science community grows especially critical during the ongoing dark time of the Advanced Photon Source in Chicago, which massively reduces available in situ synchrotron user time in North America.

58 GEOSCIENCES↗
DOE OSTI2021

Ir-192 radioisotope replacement with a hand-portable 1 MeV Ku-band electron linear accelerator

Although linear accelerators are used in many security, industrial and medical applications, the existing technologies are too large and expensive for several critical applications such as radioactive source replacement, field radiography and mobile cargo scanners. Here, one of the main requirements for these sources is to be highly portable to allow field operation. In response to this problem, RadiaBeam has designed a hand-portable 1 MeV X-ray source, scalable to higher energies, based on Ku-band split electron linac, that can be used for Ir-192 radioisotope replacement. In this paper, we present its multiphysics and engineering design studies, as well as an accelerating structure prototype along with RF measurements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Heteroatom substitution for the development of near-IR lumiphores

Near-IR (NIR) lumiphores are advantageous for biological applications as their emission falls within the tissue-transparent region. Furthermore, these dyes suffer from low quantum yields as a consequence of their low transition energy. Heteroatom substitution has recently been successfully used to bathochromically shift emission in various dye scaffolds while maintaining bright emission.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Acceleration of Near-IR Emission through Efficient Surface Passivation in Cd 3 P 2 Quantum Dots

Fast near-IR (NIR) emitters are highly valuable in telecommunications and biological imaging. The most established NIR emitters are epitaxially grown In x Ga 1-x As quantum dots (QDs), but epitaxial growth has several disadvantages. Colloidal synthesis is a viable alternative that produces a few NIR-emitting materials, but they suffer from long photoluminescence (PL) times. These long PL times are intrinsic in some NIR materials (PbS, PbSe) but are attributed to emission from bright trapped carrier states in others. We show that Cd 3 P 2 QDs possess substantial trap emission with radiative times >10 1 ns. Surface passivation through shell growth or coordination of Lewis acids is shown to accelerate the NIR emission from Cd 3 P 2 QDs by decreasing the amount of trap emission. This finding brings us one step closer to the application of colloidally synthesized QDs as quantum emitters.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Laterally Modulating Carrier Concentration by Ion Irradiation in CdO Thin Films for Mid‐IR Plasmonics

This report demonstrates tunable carrier densities in CdO thin films through local ion irradiation, providing lateral control of mid‐IR optical properties. Ion‐solid interactions produce donor‐like defects that boost electron concentrations from the practical minimum of 2.5 × 10 19 cm −3 to a maximum of 2.5 × 10 20 cm −3 by metered ion exposure. This range is achieved using He, N, Ar, or Au ions at 1–2.8 MeV; when normalized by displacements per atom, all ion species produce comparable results. Since CdO is well‐described by the Drude model, irradiation‐tuned carrier densities directly alter the infrared dielectric function, and in turn, mid‐infrared optical properties. Further, it is demonstrated that by combining irradiation with traditional lithography, CdO films expose to ions in the presence of 3‐µm thick, patterned photoresist exhibit lateral carrier density profiles with ≈400‐nm resolution. Scanning near‐field optical microscopy reveals sharp optical interfaces with almost no companion contrast in surface morphology, microstructure, or crystallinity. Finally, CdO lateral homostructures supporting surface plasmon polaritons (SPPs) are demonstrated whose dispersion relation can be tuned through periodic patterning in a monolithic platform by simple nanofabrication. Numerical simulations show these polaritons result from strong coupling between excitations at CdO plasma frequencies and SPPs supported by the platinum substrate.

cadmium oxide↗