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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Orientation Control in Epitaxial PdO Thin Films Grown on MgO (001) – Role of Oxygen Chemical Potential

Control of crystal orientations in thin films of functional materials allowsedictive tuning of their strain states, electronic properties, and surface chemical reactivity. Here, conditions for orientation control in epitaxial PdO films are investigated. Due to its tetragonal structure, PdO can form two orientational relationships with the MgO (001). It is shown that, under an oxygen-rich environment provided by oxygen-plasma-assisted molecular beam epitaxy, both (00l)- and (100)-oriented PdO domains form on MgO (001). Subsequent thermal annealing in a vacuum promotes film restructuring to a predominantly (100)-oriented PdO with improved crystallinity. Ab initio calculations reveal that the (001) orientation has lower strain energy but weaker interfacial interactions and serves as an oxygen vacancy sink, whereas the (100) orientation benefits from significantly stronger MgO─PdO bonding. Consequently (100)-oriented domains become favored under oxygen-poor conditions. A mechanism is proposed whereby vacuum annealing drives orientation transformation by generating oxygen vacancies that destabilize the (001) domains and promote (100) ordering. These findings deepen the understanding of how oxygen content impacts interfacial stability and reorganization, thereby offering a route to tune domain orientations in oxide thin films.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Merging of Thin- and Thick-Film Fabrication Technologies: Toward Soft Stretchable “Island-Bridge” Devices

Soft stretchable thick–thin-film devices are prepared by merging different fabrication technologies with different functional materials. The new “island–bridge” devices rely on screen-printed thick-film island electrodes, connected by thin-film serpentine interconnects. Furthermore, such a hybrid fabrication process enables to realize high-performance stretchable materials toward a new class of soft electronics with new capabilities that cannot be achieved via individual fabrication routes.

36 MATERIALS SCIENCE↗
DOE OSTI2025

A General Strategy for Bandgap Engineering Via Anion‐Lattice Doping in High‐Entropy Oxides

Bandgap engineering is a critical tool for tailoring the electronic properties of functional materials, traditionally achieved by modifying the cation sublattice. Here, a generalizable strategy is introduced that leverages facile anion-lattice doping in high entropy materials to modulate the bandgap in high-entropy metal oxides (HEMOs). By incorporating nitrogen into a single-phase high-entropy metal oxide/nitride (HEMO:HEMN) solid solution, a substantial bandgap reduction is achieved from 3.55 eV (HEMO) to ≈2.46 eV (HEMO:HEMN), significantly enhancing electronic conductivity. Unlike conventional bandgap tuning approaches that rely on cation substitution or heterojunction formation, this method exploits anion-mediated entropy stabilization, enabling uniform bandgap narrowing across the entire solid solution. This anion-lattice engineering strategy is broadly applicable to high-entropy systems, providing a new pathway for designing energy materials with tailored electronic properties. The resulting HEMO:HEMN solid solution exhibits a tenfold increase in capacitance and capacity compared to HEMO in supercapacitor and lithium-ion battery tests, demonstrating the transformative potential of anion-driven bandgap modulation for next-generation energy storage and conversion technologies.

energy storage↗
DOE OSTI2017

Back Contact Engineering for Increased Performance in Kesterite Solar Cells

The thin-film photovoltaic absorber Cu 2 ZnSn(S,Se) 4 (CZTSSe) holds considerable promise for large scale conversion of sunlight into electricity. CZTSSe is composed of Earth-abundant elements that exhibit low-toxicities, but improvements in device efficiency have been hampered by difficulties in increasing open circuit voltages (V OC ) due, at least in part, to disorder induced band tailing. We present a method to increase VOC through direct modification of the back contact; our approach involves the separation of fully functioning devices from their Mo/glass substrate to reveal the back CZTSSe surface. Formation of a new back contact consisting of a thermally deposited high work function material (MoO 3 ), together with a higly reflective (Au) capping layer, creates an electrostatic field that drives electrons to the front p-n junction and leads to a decrease in electron-hole recombination. Model simulations indicating an increase in V OC with decreasing absorber thickness are borne out by experiments with devices of varying thicknesses (0.7–2.0 μm). We report VOC increases of up to 49 mV for a 1 μm thick absorber, with even greater increases up to 61 mV when the back CZTSSe surface is etched with bromine-methanol.

14 SOLAR ENERGY↗
DOE OSTI2020

A Comprehensive Review on the Development of Solid–State Metal–Air Batteries Operated on Oxide–Ion Chemistry

The recently developed solid oxide metal–air redox battery (SOMARB) operating on oxide-ion chemistry represents an emerging and promising energy storage technology, which is well suited for managing grid stability and efficiently harvesting renewable energy. Compared to widely reported metal–air batteries operating on liquid-phase alkali-ion or alkaline chemistries, the SOMARB uniquely features a direct reduction of the high concentration of O 2 molecules in the gas phase without invoking the detrimental formation of a diffusion-blocking oxide phase on the surface of the oxygen electrode. A typical SOMARB is composed of a reversible solid oxide cell (RSOC) and an energy storage unit (ESU), which is capable of storing a high capacity of energy at high power without safety concerns. In this article, the SOMARB concept birth and development are reviewed and discussed with the fundamental differences separating it from other types of metal–air batteries, along with the challenges and opportunities around commercialization. Particular focus is placed on the functional materials tailored for ESU and RSOC applications, including recent experimental and computational efforts to boost the redox activity of Fe-based ESU materials and the performance of intermediate temperature RSOCs. Lastly, candid opinions are offered on the challenges and opportunities facing the future development of SOMARBs toward large-scale energy storage applications.

08 HYDROGEN↗
DOE OSTI2018

Design Rules for Self-Assembly of 2D Nanocrystal/Metal–Organic Framework Superstructures

Here, we demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe 3 O 4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand–ligand interactions between surface ligands on Fe 3 O 4 NCs and Zr 6 O 4 (OH) 4 (fumarate) 6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe 3 O 4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand–surface and ligand–ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Controlling Dissolution and Transformation of Zeolitic Imidazolate Frameworks by using Electron‐Beam‐Induced Amorphization

Abstract Amorphous zeolitic imidazolate frameworks (ZIFs) offer promising applications as novel functional materials. Herein, amorphization of ZIF‐L through scanning‐electron‐beam exposure is demonstrated, based on amorphization of individual ZIF‐L crystals. The amorphized ZIF product has drastically increased stability against dissolution in water. An electron dose that allows for complete preservation of amorphous particles after immersion in water is established, resulting in new shapes of amorphous ZIF‐L with spatial control at the sub‐micrometer length scale. Changed water stability as a consequence of scanning‐electron‐beam exposure is demonstrated for three additional metal–organic frameworks (ZIF‐8, Zn(BeIm)OAc, MIL‐101), highlighting the potential use of an electron beam for top‐down MOF patterning. Lastly, recrystallization of ZIF‐L in the presence of linker is studied and shows distinct differences for crystalline and amorphized material.

Conrad, Sabrina↗
DOE OSTI2018

Design Rules for Self-Assembly of 2D Nanocrystal/Metal-Organic Framework Superstructures

Here we demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe 3 O 4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand–ligand interactions between surface ligands on Fe 3 O 4 NCs and Zr 6 O 4 (OH) 4 (fumarate) 6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe 3 O 4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand–surface and ligand–ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Polypeptoid polymers: Synthesis, characterization, and properties

Polypeptoids, a class of peptidomimetic polymers, have emerged at the forefront of macromolecular and supramolecular science and engineering as the technological relevance of these polymers continues to be demonstrated. The chemical and structural diversity of polypeptoids have enabled access to and adjustment of a variety of physicochemical and biological properties (eg, solubility, charge characteristics, chain conformation, HLB, thermal processability, degradability, cytotoxicity and immunogenicity). These attributes have made this synthetic polymer platform a potential candidate for various biomedical and biotechnological applications. Furthermore, this review will provide an overview of recent development in synthetic methods to access polypeptoid polymers with well–defined structures and highlight some of the fundamental physicochemical and biological properties of polypeptoids that are pertinent to the future development of functional materials based on polypeptoids.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Electrochemical Applications of Microphase-Separated Block Copolymer Thin Films

In this work, we discuss electrochemical applications of electrode-supported thin films derived from microphase-separated block copolymers (BCPs). In contrast to conventional homopolymers used for electrode modification, BCPs afford periodic nanoscale structures (microdomains) of uniform dimensions (5-100 nm) and predictable morphologies, which can be controlled by adjusting the lengths of individual homopolymer segments. BCPs usable for electrochemical applications consist of two or more segments that form solute-permeable, redox-active or etchable microdomains and a chemically inert matrix. The resulting microdomains afford nanoscale molecular/charge transport pathways toward the underlying electrode, whereas the matrix serves as a scaffold to improve film stability in a solution. In conclusion, these polymeric thin films provide a unique means for fabricating nanowire arrays via template-based electrochemical synthesis, designing electrochemical sensors with unique selectivity, and constructing electrochemically-tunable functional materials.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Fullerene "Superhalogen" Radicals: The Substituent Effect on Electronic Properties of 1,7,11,24,27-C60X5

Hexasubstituted fullerenes with the skew pentagonal pyramid (SPP) addition pattern are predominantly formed in many types of reactions and represent important and versatile building blocks for supramolecular chemistry, biomedical and optoelectronic applications. Regioselective synthesis and characterization of the new SPP derivative, C60(CF3)4(CN)H, in this work led us to the experimental identification of the new family of "superhalogen fullerene radicals", species with the gas-phase electron affinity higher than that of the most electronegative halogens, F and Cl. Low-temperature photoelectron spectroscopy and DFT studies of different C60X5 radicals reveal a profound effect of X groups on their electron affinities (EA), which vary from 2.76 eV (X = CH3) to 4.47 eV (X= CN). The measured gas-phase EA of the newly synthesized C60(CF3)4CN equals 4.28 (1) eV, which is ca. 1 eV higher than the EA of Cl atom. An observed remarkable stability of C60(CF3)4CN– in solution under ambient conditions opens new venues for design of air-stable molecular complexes and salts for supramolecular structures of electroactive functional materials.

electron affinity↗
DOE OSTI2023

Advances in Regioselective Functionalization of Endohedral Metallofullerenes †

Comprehensive Summary Endohedral metallofullerenes (EMFs) are a family of molecules with metal clusters or ions encapsulated inside a fullerene cage. Their unique structures provide a powerful interface for organic chemists to manipulate metal elements. Over a decade ago, many reactions on empty fullerenes were adopted for EMFs, resulting in a series of reactions that are well‐established and reviewed in the literature. In recent years, new topics have emerged in EMF chemistry. First, new addition reactions were developed, notably some that are not based on known empty‐fullerene reactions. Second, considerable progress has been made on regioselective multi‐additions on EMFs. Finally, EMFs have been covalently conjugated with fullerene C 60 to form functional materials. This Recent Advances article will focus on these new developments and discuss their implication for future directions of EMFs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Probing the Kinetic Origin of Varying Oxidative Stability of Ethyl- vs. Propyl-spaced Amines for Direct Air Capture

Amine-based adsorbents are promising for direct air capture of CO 2 , yet oxidative degradation remains a key unmitigated risk hindering wide-scale deployment. Borrowing wisdom from the basic auto-oxidation scheme, insights are gained into the underlying degradation mechanisms of polyamines by quantum chemical, advanced sampling simulations, adsorbent synthesis, and accelerated degradation experiments. The reaction kinetics of polyamines are contrasted with that of typical aliphatic polymers and they elucidate for the first time the critical role of aminoalkyl hydroperoxide decomposition in the oxidative degradation of amino-oligomers. The experimentally observed variation in oxidative stability of polyamines with different backbone structures is explained by the relationship between the local chemical structure and the free energy barrier of aminoalkyl hydroperoxide decomposition, suggesting that its energetics can be used as a descriptor to screen and design new polyamines with improved stability. In conclusion, the developed computational capability sheds light on radical-induced degradation chemistry of other organic functional materials.

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

Polymer Waste Valorization into Advanced Carbon Nanomaterials for Potential Energy and Environment Applications

The rise in universal population and accompanying demands have directed toward an exponential surge in the generation of polymeric waste. The estimate predicts that world-wide plastic production will rise to ≈590 million metric tons by 2050, whereas 5000 million more tires will be routinely abandoned by 2030. Handling this waste and its detrimental consequences on the Earth's ecosystem and human health presents a significant challenge. Converting the wastes into carbon-based functional materials viz. activated carbon, graphene, and nanotubes is considered the most scientific and adaptable method. Herein, this world provides an overview of the various sources of polymeric wastes, modes of build-up, impact on the environment, and management approaches. Update on advances and novel modifications made in methodologies for converting diverse types of polymeric wastes into carbon nanomaterials over the last 5 years are given. A remarkable focus is made to comprehend the applications of polymeric waste-derived carbon nanomaterials (PWDCNMs) in the CO 2 capture, removal of heavy metal ions, supercapacitor-based energy storage and water splitting with an emphasis on the correlation between PWDCNMs' properties and their performances. In conclusion, this review offers insights into emerging developments in the upcycling of polymeric wastes and their applications in environment and energy.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Nanofabrication with Metallopolymers: Recent Developments and Future Perspectives

We found that synthetic polymers containing metals and metal centers have experienced rapid growth in the last two decades. Metal-containing polymers and these have an unprecedented role to play in modern high-tech applications including nanomanufacturing, sensing, separation and catalysis. Advancement in synthetic strategies for macromolecules has enabled the synthesis of novel, exotic and use-inspired metallopolymers. Using state-of-the-art design strategies, it is now possible to perform targeted synthesis of macromolecules with varied complexity that contain a range of metal centers either in the backbone or in the side chains of the organic moiety. Moreover, the presence of an inorganic element (metals and metal centers) in organic moieties has led to a number of new physicochemical properties while implementing novel functionality to the polymer matrix. This review covers nanotechnology influenced by distinctive features of metal-containing macromolecular systems, particularly in developing flexible, functional materials.

36 MATERIALS SCIENCE↗