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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Thermally restorable optical degradation effects in heat-treated Cu2S-CdS crystal heterojunctions.

We have shown that heat treatment alone does not produce appreciable degradation of the short-circuit current in Cu2S-CdS single-crystal photovoltaic heterojunctions. The degradation, which has been commonly observed, is the result of optically induced effects in the heat-treated cell, subsequent to the heat treatment. These optically induced effects can be correlated with photochemical changes induced in single crystals of CdS:Cd:Cu in which the density of Cu acceptors exceeds the density of excess-Cd donors. Major conclusions about the mechanism of the photovoltaic effect and heat-treatment processes can be drawn.

Kanev, S. K.↗
NASA NTRS1971

Inorganic photochromic and cathodochromic recording materials.

Discussion of studies at RCA Laboratories of the properties of rare-earth-doped CaF2, transition-metal-doped SrTiO3 and iron- or sulfur-doped sodalite as photochromic materials which change color during light or electron beam exposures. Particular attention is given to their photochromic characteristics in single-crystal and powder forms and to their cathodochromic properties in powder form. Details are given on the photochromic mechanisms, spectra, optical density, thermal decay rates, and coloring and bleaching efficiency of their single crystals and on the diffuse reflectance spectra, saturated photochromic contrast ratio, switching and erase sensitivities, and cathodochromic excitation of their photochromic powders. The many attractive characteristics of these materials when used in display storage systems are indicated.

Duncan, R. C., Jr.↗
NASA NTRS1972

Optically erasable and rewritable solid-state holograms.

Optical holographic storage in single-crystal LiNbO3 is described which can be optically erased at room temperature and then rewritten with no degradation in efficiency or writing rate. The diffraction efficiencies associated with the process are about 0.0001. Some variations from previously obtained results include a lack of threshold power density for writing, very-long-term persistence of the stored hologram, and a lack of a dependence of the diffracted intensity on the polarization of the readout beam.

Gaylord, T. K.↗
NASA NTRS1972

Petrology of basaltic and monomineralic soil fragments from the Sea of Fertility.

Basaltic and monomineralic fragments from the 150-425 micron size fractions of the Luna 16 core obtained from the Sea of Fertility were studied by optical petrographic, electron microprobe, and single-crystal X-ray diffraction techniques. Three textural varieties were identified in the basalts (intersertal, subophitic, and recrystallized). These textures, the assemblages, and individual mineral compositions (especially pyroxenes) indicate that these basalts crystallized under conditions very similar to those from Apollo 11. The pyroxenes have slightly lower Ti/Al (atomic) ratios than the Apollo 11 pyroxenes. We interpret the presence of octahedral Al as being due to the low TiO2/Al2O3 (weight %) ratio in the bulk rock. All observations made on the fine-grained basalt fragments are consistent with a rapid, near-surface, one-stage crystallization history.

Bence, A. E.↗
NASA NTRS1972

Apollo 14 inverted pigeonites - Possible samples of lunar plutonic rocks.

Analysis of 'inverted pigeonites' found in Apollo 14 samples 14082 and 14083 (a polymict breccia, the 'white rock') by a combination of optical, electron probe, and single-crystal X-ray diffraction techniques. These 'inverted pigeonites' are regarded as samples of plutonic rocks that have been blasted out of the Imbrium Basin. It is also concluded that lunar pigeonites will invert to orthopyroxenes, given sufficiently slow cooling histories even in very anhydrous environments.

Papike, J. J.↗
NASA NTRS1972

Photocapacitance effects at a Cu2S-CdS heterojunction.

The influence of trapped charge on the photovoltaic properties of an efficient Cu2S-CdS single-crystal heterojunction has been studied by a photocapacitance technique. For the nonheat-treated cell, a persistent increment in capacitance as high as 70% of the dark capacitance remained after illumination of the junction by band-gap light at 100 K. The additional capacitance is due to holes trapped in deep levels in the CdS depletion region near the interface. The trapped holes enhanced the 100 K photocurrent spectrum uniformly by a factor of 3 before heat treatment. After a 200 C heat treatment in air, the maximum trapped charge at 100 K enhanced the photocurrent by two orders of magnitude. The results are interpreted in terms of the tunneling through a conduction band spike of electrons photoexcited in the Cu2S.

Lindquist, P. F.↗
NASA NTRS1972

Elasticity of some mantle crystal structures. I - Pleonaste and hercynite spinel.

The elasticity of high-pressure mantle phases can be characterized by using data for chemically similar crystal compounds. The single-crystal elastic constants are determined as a function of pressure and temperature for pleonaste spinel and at room conditions for hercynite spinel. The bulk modulus increases from 1.95 Mb for pleonaste spinel to 2.10 Mb for hercynite spinel. Low or negative values of the pressure derivatives of shear constants are characteristic of the spinel structure and imply a low kinetic barrier to phase transformations and diffusion. Compressional and shear velocities of the spinel phase of olivine are estimated as a function of mean atomic weight by using the pleonaste and hercynite data.

Wang, H.↗
NASA NTRS1972

Thermal conductivity of earth materials at high temperatures.

The total thermal conductivity (lattice plus radiative) of several important earth materials is measured in the temperature range from 500 to 1900 K. A new technique is used in which a CO2 laser generates a low-frequency temperature wave at one face of a small disk-shaped sample, and an infrared detector views the opposite face to detect the phase of the emerging radiation. Phase data at several frequencies yield the simultaneous determination of the thermal diffusivity and the mean extinction coefficient of the material. The lattice, radiative, and total thermal conductivities are then calculated. Results for single-crystal and polycrystalline forsterite-rich olivines and an enstatite indicate that, even in relatively pure large-grained material, the radiative conductivity does not increase rapidly with temperature. The predicted maximum total thermal conductivity at a depth of 400 km in an olivine mantle is 0.020 cal/cm/sec/deg C, which is less than twice the surface value.

Schatz, J. F.↗
NASA NTRS1973

Shock wave compression of iron-silicate garnet.

Shock wave compression data to over 650 kb are presented for single-crystal almandine garnet. The data indicate the initiation of a phase transformation near 200 kb. Total transition to the high-pressure polymorph occurs at approximately 300 kb. The elastic properties of the high-pressure phase are calculated from the metastable Hugoniot data by using the linear shock velocity-particle velocity relationships. The overall results obtained strongly suggest that upper mantle minerals are likely to occur in the ilmenite structure over a substantial part of the lower mantle.

Graham, E. K.↗
NASA NTRS1973

Elasticity of some mantle crystal structures. II.

The single-crystal elastic constants are determined as a function of pressure and temperature for rutile structure germanium dioxide (GeO2). The data are qualitatively similar to those of rutile TiO2 measured by Manghnani (1969). The compressibility in the c direction is less than one-half that in the a direction, the pressure derivative of the shear constant is negative, and the pressure derivative of the bulk modulus has a relatively high value of about 6.2. According to an elastic strain energy theory, the negative shear modulus derivative implies that the kinetic barrier to diffusion decreases with increasing pressure.

Wang, H.↗
NASA NTRS1973

A shock-induced phase change in orthoclase.

New shock compression data to 340 kb for single-crystal orthoclase (along (001)), demonstrate the onset of a shock-induced phase change at about 115 kb. Along the Hugoniot a mixed-phase region extends to about 300 kb, above which the data are believed to correspond to the properties of a high-pressure phase having the hollandite structure (zero pressure density of 3.84 g/cu cm) reported by Ringwood et al. If the hollandite value for the zero pressure density is used, the zero pressure bulk modulus of this phase is approximately 1.8 plus or minus 0.2 Mb.

Ahrens, T. J.↗
NASA NTRS1973

Petrology of fine-grained rock fragments and petrologic implications of single crystal from the Luna 20 soil.

Only fine-grained rocks are present in the Luna 20 samples, and coarser-grained rocks are represented by fragments of single crystals. A petrologic study has been made of 47 fine-grained crystalline rocks, microbreccias, and glassy aggregates. In addition, a total of 33 single crystals of pyroxene, plagioclase, olivine, and spinel, in the size range from 125 to 500 microns, have been examined using electron microprobe and single-crystal X-ray diffraction techniques. The most abundant fine-grained crystalline rocks in the samples examined are recrystallized anorthositic norite and anorthositic troctolite. Gabbroic rocks, anorthosite, and KREEP basalt are present but not common. Most of the single crystals of pyroxene and plagioclase could have been derived from coarser-grained noritic, troctolitic, and anorthositic rocks. However, three of the 14 pyroxene crystals, and two of the five olivine crystals have Fe/(Fe + Mg) contents greater than 0.45 and are believed to have been derived from mare basalts or related rocks.

Cameron, K. L.↗
NASA NTRS1973

Surface segregation in titanium as monitored by Auger electron spectroscopy

Investigation of the surface diffusion and segregation of bulk impurities in titanium single crystals under well-defined and controlled experimental conditions. It is shown that an atomically clean titanium single-crystal surface can be obtained by argon ion bombardment within the temperature range from 700 to 800 C. It is demonstrated by Auger electron spectroscopy that, if such clean surfaces are subjected to thermal treatment, bulk impurities, especially sulfur, diffuse out to the crystal surface, and that the rate of surface segregation increases with increasing temperature.

Khan, I. H.↗
DOE OSTI2026

Oxide-nitride heteroepitaxy for low-loss dielectrics in superconducting quantum circuits

Superconducting qubits show great promise for the realization of fault-tolerant quantum computing, but lossy, amorphous dielectrics limit current technology. Identifying highly crystalline and stoichiometric dielectrics with intrinsically low microwave loss is therefore a central materials challenge, yet experimentally validated platforms remain scarce. In this work, we integrate a crystalline dielectric into a heteroepitaxial TiN/$γ$-Al$_2$O$_3$/TiN trilayer grown via pulsed laser deposition. Correlative high-resolution imaging, diffraction, and spectroscopy measurements confirm the single-crystal quality and chemical integrity of all layers, with minimal defects and limited anion interdiffusion across the oxide-nitride interfaces. Using microwave lumped-element resonators with parallel-plate capacitors, we report the first direct measurement of the dielectric loss of epitaxial $γ$-Al$_2$O$_3$, for which we find a low intrinsic two-level system loss, $δ_{\text{TLS}}^0 = (2.8 \pm 0.1) \times 10^{-5}$. These results establish heteroepitaxial oxides on transition metal nitrides as an attractive materials platform for superconducting quantum circuits, particularly for integration into compact device architectures such as merged-element transmons and microwave kinetic inductance detectors.

Garcia-Wetten, David A. [Northwestern U.]↗
DOE OSTI2026

Thermoelectric Behavior of Structurally Disordered Lanthanide and Actinide Silicides

Lanthanide and actinide intermetallic materials exhibit intriguing electronic, structural, and magnetic properties arising from their partially filled f orbitals. Strong f-electron correlations can significantly modify the electronic density of states, carrier scattering, and transport behavior, making these systems promising candidates for unconventional thermoelectric materials. In previous studies, single crystals of A1.33T4Al8Si2 (A = Ce, Th, U, Np; T = Co, Ni) were synthesized. This structure consists of ordered TAl2 corrugated double layers separated by disordered An–Si monolayers. The inherent disorder within the An–Si layers has been linked to unusual magnetic behavior, such as spin-glass phenomena, and is expected to strongly influence phonon scattering and charge-carrier transport relevant to thermoelectric performance. However, the thermoelectric properties of this material family have not previously been explored. In this work, DFT calculations were performed to evaluate the electronic density of states, band structures, and thermoelectric properties, including the effects of doping. To validate these predictions, Ce1.33Co4Al8Si2 single crystals were grown and experimentally characterized. Additionally, a new Yb1.33Co4Al8Si2 phase was synthesized and characterized using single-crystal XRD, SEM-EDS, magnetization measurements, and thermoelectric measurements. These results provide insight into structure–property relationships governing thermoelectric behavior in f-electron intermetallics and offer guidance for future thermoelectric materials.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
DOE OSTI2025

Flux Upcycling of Degraded Layered Cathodes to LiNi x Mn y Co z O 2 (NMCs) with Gradient Transition Metal Distribution

The rising demand for lithium-ion batteries (LIBs) has intensified the need for efficient recycling methods to address both supply chain constraints and environmental impacts. Direct upcycling, distinguished by its ability to achieve both the structural and compositional integrity of cathode materials, has gained prominence as a sustainable alternative to conventional pyrometallurgical and hydrometallurgical processes. However, the current direct upcycling methods are typically limited by incorporating Li and/or Ni, significantly constraining the adaptability across diverse LiNi x Mn y Co z O 2 (NMCs). Here, in this study, a versatile molten salt approach is reported that expands the scope of direct upcycling by enabling simultaneous incorporation of Li, Ni, and Mn. This methodology facilitates flexible conversion among diverse NMC compositions, including non-stoichiometric Co/Mn systems such as upcycling degraded LiCoO 2 (D-LCO), LiNi 1/3 Mn 1/3 Co 1/3 O 2 (D-NMC111), LiNi 0.8 Mn 0.1 Co 0.1 O 2 (D-NMC811) to surface Mn enriched NMC111, LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), and NMC811, respectively. The gradient transition metal distribution in upcycled products, characterized by Mn-enriched outer layers and Co/Ni-enriched cores enhances the interfacial stability of NMC cathodes, addressing critical challenges in long-term performance and structural integrity. These results highlight the potential of flux methods for advancing the upcycling of spent cathodes and producing high-performance materials for next-generation LIBs applications.

lithium -ion batteries↗
DOE OSTI2026

Upcycling Polycrystalline LiNi1/3Mn1/3Co1/3O2 to High-Performance Large-Grained LiNi0.6Mn0.2Co0.2O2 via Simplified Polyol-Mediated Recycling

The escalating demand for lithium-ion batteries (LIBs) necessitates advanced recycling strategies that can address both resource scarcity and environmental impact. While conventional hydrometallurgy shows promise, it is challenged by complexity, impurity management, and environmental footprint. Here, we report a strategic polyol-metallurgy recycling process that efficiently transforms spent polycrystalline LiNi1/3Mn1/3Co1/3O2 (NMC111) into high-performance large-grained LiNi0.6Mn0.2Co0.2O2 (NMC622), offering dual benefits of compositional upcycling and morphology upgradation. Our approach leverages a polyol system with meticulous control over nickel salt addition and the precipitation process. This yields upcycled cathode materials possessing excellent structural integrity, well-defined large-grained particles (5-10?..mu..m), and robust electrochemical performance, including a specific capacity of ~182 mAh g-1 at C/10 and 88.0% capacity retention after 100 cycles. This facile and multifunctional process provides an environmental-friendly pathway for advanced cathode recycling, significantly contributing to a circular economy for LIBs through precise control over critical material attributes.

25 ENERGY STORAGE↗
DOE OSTI2025

Interplay Between Metastability and Mechanically Induced Structural Instability in CsPbBr 3 Photovoltaic Perovskite

An atomic-level understanding of the underlying structural metastability is still absent in halide perovskite photovoltaic systems. Focusing on the model material CsPbBr 3 , the impact of mechanically induced atomic structure alteration is elucidated through structural modeling and X-ray diffraction measurements. Sudden Cs–Br bond breaking drives the system metastability, where the first-order transition arises from cation-halide bond strain relief by severing the corner connectivity of the PbBr 6 units. The pressure–volume and entropy terms govern the Gibbs free-energy landscape in halide perovskites. In conclusion, metastability is revealed as a critical factor limiting the performance of lead halide perovskites under extreme but natural environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗