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DOE OSTI2023

Nanographene Coupled with Interfacial Pyrene Derivatives for Thermally Stable Perovskite Solar Cells

Although high-efficiency perovskite solar cells (PSCs) have been achieved using a hole-extracting material, spiro-MeOTAD, thermal stability has been unattainable due to the low glass transition temperature of spiro-MeOTAD and additives therein. In this paper we report on the use of nanographene-based hole-transporting materials coupled with a pyrene derivative as an interface modifier for thermally stable and high efficiency PSCs. Asymmetric methyl and methoxy groups are introduced in the diphenylamino group that is attached to the hexa-peri-hexabenzocoronene (HBC) nanographene core, coded HBC-DPAMeOMe. 1-Pyrenemethylammonium iodide is coupled to enhance the chemical interaction between perovskite and HBC-DPAMeOMe, which leads to a power conversion efficiency over 23%. A thermal stability test at 85 degrees C for 1000 h reveals that 83.6% of the initial efficiency (23.04% --> 19.25%) is maintained for the device with HBC-DPAMeOMe, while a significant degradation from 20.69% to 5.08% is observed for the device with spiro-MeOTAD. Nanographene-based hole conductors shed light on the thermal stability issue in PSCs.

14 SOLAR ENERGY↗

DOE OSTI2024

FPGA-Accelerated Range-Limited Molecular Dynamics

Long timescale Molecular Dynamics (MD) simulation of small molecules is crucial in drug design and basic science. To accelerate a small data set that is executed for a large number of iterations, high-efficiency is required. Recent work in this domain has demonstrated that among COTS devices only FPGA-centric clusters can scale beyond a few processors. The problem addressed here is that, as the number of on-chip processors has increased from fewer than 10 into the hundreds, previous intra-chip routing solutions are no longer viable. We find, however, that through various design innovations, high efficiency can be maintained. These include replacing the previous broadcast networks with ring-routing and then augmenting the rings with out-of-order and caching mechanisms. Others are adding a level of hierarchical filtering and memory recycling. Two novel optimized architectures emerge, together with a number of variations. These are validated, analyzed, and evaluated. We find that in the domain of interest speed-ups over GPUs are achieved. Finally, the potential impact is that this system promises to be the basis for scalable long timescale MD with commodity clusters.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2020

The Minos Computing Library: Efficient Parallel Programming for Extremely Heterogeneous Systems

Hardware specialization has become the silver bullet to achieve efficient high performance, from Systems-on-Chip systems, where hardware specialization can be ``extreme'', to large-scale HPC systems. As the complexity of the systems increases, so does the complexity of programming such architectures in a portable way. This work introduces the Minos Computing Library (MCL), as system software, programming model, and programming model runtime that facilitate programming extremely heterogeneous systems. MCL supports the execution of several multi-threaded applications within the same compute node, performs asynchronous execution of application tasks, efficiently balances computation across hardware resources, and provides performance portability. We show that code developed on a personal desktop automatically scales up to fully utilize powerful workstations with 8 GPUs and down to power-efficient embedded systems. MCL provides up to 17.5x speedup over OpenCL on NVIDIA DGX-1 systems and up to 1.88x speedup on single-GPU systems. In multi-application workloads, MCL dynamically resource allocation provides up to 2.43x performance improvement over manual, static allocation of computing resources.

Gioiosa, Roberto↗

DOE OSTI2023

Status and future plans for C 3 R&D

C 3 is an opportunity to realize an e + e - collider for the study of the Higgs boson at √s = 250 GeV, with a well defined upgrade path to 550 GeV while staying on the same short facility footprint. C 3 is based on a fundamentally new approach to normal conducting linear accelerators that achieves both high gradient and high efficiency at relatively low cost. Given the advanced state of linear collider designs, the key system that requires technical maturation for C 3 is the main linac. This paper presents the staged approach towards a facility to demonstrate C 3 technology with both Direct (source and main linac) and Parallel (beam delivery, damping ring, ancillary component) R&D. The primary goal of the C 3 Demonstration R&D Plan is to reduce technical and cost risk by building and operating the key components of C 3 at an adequate scale. This R&D plan starts with the engineering design, and demonstration of one cryomodule and will culminate in the construction of a 3 cryomodule linac with pre-production prototypes. This R&D program would also demonstrate the linac rf fundamentals including achievable gradient and gradient stability over a full electron bunch train and breakdown rates. It will also investigate beam dynamics including energy spread, wakefields, and emittance growth. This work will be critical to confirm the suitability of the C 3 beam parameters for the physics reach and detector performance in preparation for a Conceptual Design Report (CDR), as well as for follow-on technology development and industrialization. The C 3 Demonstration R&D Plan will open up significant new scientific and technical opportunities based on development of high-gradient and high-efficiency accelerator technology. It will push this technology to operate both at the GeV scale and mature the technology to be reliable and provide high-brightness electron beams. The timeline for progressing with C 3 technology development will be governed by practical limitations on both the technical progress and resource availability. It consists of four stages: Stage 0) Ongoing fundamental R&D on structure prototypes, damping and vibrations. Stage 1) Advancing the engineering maturity of the design and developing start-to-end simulations including space-charge and wakefield effects. This stage will include testing of strucutres operating at cryogenic temperatures. Beam tests would be performed with high beam current to test full beam loading. Stage 2) Production and testing of the first cryomodule at cryogenic temperatures. This would provide sufficient experimental data to compile a CDR and it is anticipated for Stage 2 to last 3 years and to culminate with the transport of photo-electrons through the first cryomodule. Stage 3) Updates to the engineering design of the cryomodules, production of the second and third cryomodule and their installation. Lower charge and lower emittance beams will be used to investigate emittance growth. The successful full demonstration of the 3 cryomodules to deliver up to a 3 GeV beam and achieve the C 3 five gradient will allow a comprehensive and robust evaluation of the technical design of C 3 as well as mitigate technical, schedule, and cost risks required to proceed with a Technical Design Report (TDR).

radiation hardened magnets↗

DOE OSTI2021

On-Device Lead Detention for Perovskite Solar Cells

As the power conversion efficiency (PCE) of perovskite solar cells (PSCs) have reached above 25.5%, the commercialization of PSCs appears to be imminent due to its lower fabrication cost, simpler manufacturing processes, and larger processing area over Si-based solar cells that dominate the current photovoltaic (PV) market. While many efforts have focused on tackling the stability and scalability issues with promising advances, the potential lead (Pb) toxicity issue has remained a concern of PSCs. Unlike the metallic Pb, the Pb 2+ in perovskite generally exhibit high solubility in water. However, Pb 2+ has so far appeared to be a necessary component in all high-efficiency PSCs. Handful methods have been explored to mitigate the potential Pb2+ leaking issue, which can be generally categorized as physical encapsulation and our pioneering chemical absorption method, which was extended by others later. Since device damage is inevitable in outdoor conditions, physical encapsulation alone is not sufficient to mitigate the long-term risk of leakage of soluble Pb 2+ to the environment under severe weather conditions. As a result, the chemical absorption approach has recently attracted significant attention as a more effective solution to confine the potential lead leakage. Hence, it is of great value to develop durable and highly efficient Pb-absorbing components that can be conveniently mounted onto the standard PSC stack as an add-on accessory in line with the encapsulation of PSCs instead of modifying the standard device fabrication and/or device configuration.

14 SOLAR ENERGY↗

DOE OSTI2020

High-Performance, Long-Life, Rechargeable Li–CO 2 Batteries based on a 3D Holey Graphene Cathode Implanted with Single Iron Atoms

A highly efficient cathode catalyst for rechargeable Li-CO 2 batteries is successfully synthesized by implanting single iron atoms into 3D porous carbon architectures, consisting of interconnected N,S-codoped holey graphene (HG) sheets. The unique porous 3D hierarchical architecture of the catalyst with a large surface area and sufficient space within the interconnected HG framework can not only facilitate electron transport and CO 2 /Li+ diffusion, but also allow for a high uptake of Li 2 CO 3 to ensure a high capacity. Consequently, the resultant rechargeable Li-CO 2 batteries exhibit a low potential gap of approximate to 1.17 V at 100 mA g -1 and can be repeatedly charged and discharged for over 200 cycles with a cut-off capacity of 1000 mAh g -1 at a high current density of 1 A g -1 . Density functional theory calculations are performed and the observed appealing catalytic performance is correlated with the hierarchical structure of the carbon catalyst. This work provides an effective approach to the development of highly efficient cathode catalysts for metal-CO 2 batteries and beyond.

(2) batteries↗

DOE OSTI2024

Hierarchical Self‐Assembly of Multidimensional Functional Materials from Sequence‐Defined Peptoids

Abstract Hierarchical self‐assembly represents a powerful strategy for the fabrication of functional materials across various length scales. However, achieving precise formation of functional hierarchical assemblies remains a significant challenge and requires a profound understanding of molecular assembly interactions. In this study, we present a molecular‐level understanding of the hierarchical assembly of sequence‐defined peptoids into multidimensional functional materials, including twisted nanotube bundles serving as a highly efficient artificial light harvesting system. By employing synchrotron‐based powder X‐ray diffraction and analyzing single crystal structures of model compounds, we elucidated the molecular packing and mechanisms underlying the assembly of peptoids into multidimensional nanostructures. Our findings demonstrate that incorporating aromatic functional groups, such as tetraphenyl ethylene (TPE), at the termini of assembling peptoid sequences promotes the formation of twisted bundles of nanotubes and nanosheets, thus enabling the creation of a highly efficient artificial light harvesting system. This research exemplifies the potential of leveraging sequence‐defined synthetic polymers to translate microscopic molecular structures into macroscopic assemblies. It holds promise for the development of functional materials with precisely controlled hierarchical structures and designed functions.

Shao, Li↗

DOE OSTI2024

Hierarchical Self‐Assembly of Multidimensional Functional Materials from Sequence‐Defined Peptoids

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Using nature’s blueprint to expand catalysis with Earth-abundant metals

Original title changed for publication from; " Using Nature's Blueprint to Enable Catalysis with Earth-Abundant Metals" A diverse array of redox transformations that are essential to life are catalyzed by metalloenzymes that feature an earth-abundant metal. In contrast, platinum-group metals have been the cornerstone of many industrial catalytic reactions for decades, providing high activity, thermal stability and tolerance to chemical poisons. We assert that Nature’s blueprint provides the fundamental principles for vastly expanding the use of abundant metals in catalysis. We highlight the key physical properties of abundant metals that distinguish them from precious metals, and we look to Nature to understand how the inherent attributes of abundant metals can be embraced, leading to unique, highly efficient catalysts, emphasizing reactions crucial to the sustainable production and transformation of fuels and chemicals.

Bullock, Ronald M.↗

DOE OSTI2023

A fast two-stage algorithm for non-negative matrix factorization in smoothly varying data

This article reports the study of algorithms for non-negative matrix factorization (NMF) in various applications involving smoothly varying data such as time or temperature series diffraction data on a dense grid of points. Utilizing the continual nature of the data, a fast two-stage algorithm is developed for highly efficient and accurate NMF. In the first stage, an alternating non-negative least-squares framework is used in combination with the active set method with a warm-start strategy for the solution of subproblems. In the second stage, an interior point method is adopted to accelerate the local convergence. The convergence of the proposed algorithm is proved. The new algorithm is compared with some existing algorithms in benchmark tests using both real-world data and synthetic data. Furthermore, the results demonstrate the advantage of the algorithm in finding high-precision solutions.

interior point method↗

DOE OSTI2022

Perspective—The Role of Solid Oxide Fuel Cells in Our Carbon-Neutral Future

Solid Oxide Fuel Cells (SOFCs) offer the potential for compelling value propositions in stationary and transportation applications through their high efficiency and fuel flexibility—two critical characteristics that will allow them to facilitate our transition to a carbon neutral economy. This paper describes the overall integration synergies that can be realized in hybrid systems comprised of an SOFC and an engine bottom-cycle. The development to date is reviewed, and application-specific value propositions are explored. Finally, the environmental impact of hybrid systems are discussed, and key challenges to overcome are examined for this highly efficient conversion technology to achieve commercial success.

25 ENERGY STORAGE↗

DOE OSTI2020

Technoeconomic Analysis of Photovoltaics Module Manufacturing with Thin Silicon Wafers

Reducing silicon usage by adopting thinner wafers can significantly reduce capital expenditure (capex) and cost, and thus accelerate the growth of manufacturing capacity and deployment. In this work, we evaluated potential benefits of thin Si wafers for current and future PV modules. We apply a technoeconomic framework that couples bottom-up cost model, and a cash-flow growth model to analyze PV modules with thin wafers. First, we show that, comparing the current PERC with 160 um thick wafers to the high-efficiency concept with 50 um thin wafers, the capex is reduced from 0.39 to 0.2 $/(W/year) while the cost is from 0.32 to 0.2 $/W. Second, the potential of accelerated deployment is analyzed for the highefficiency thin wafer concept. We found the significant advantages of higher growth rate (~20% relative) and higher deployment plateau (~3 times) than the current PERC modules. modules with thin wafers. First, we show that, comparing the current PERC with 160 um thick wafers to the high-efficiency concept with 50 um thin wafers, the capex is reduced from 0.39 to 0.2 $/(W/year) while the cost is from 0.32 to 0.2 $/W. Second, the potential of accelerated deployment is analyzed for the highefficiency thin wafer concept. We found the significant advantages of higher growth rate (~20% relative) and higher deployment plateau (~3 times) than the current PERC modules.

14 SOLAR ENERGY↗

DOE OSTI2021

Technical Assessment of Novel Hydrogen Producing Solid Oxide Fuel Cell Power System

Solid oxide cell-based electrolysis (SOEC) systems are being considered for hydrogen production due to their potential for high efficiencies and for their integrability with base load power generation systems when operated in solid oxide fuel cell (SOFC) mode. However, a cost prohibitive combination of SOFC power systems and SOEC systems may be required to operate the plant flexibly to produce a combination of H 2 and power on-demand. A single (consequently less expensive) reversible SOFC/SOEC system, on the other hand, poses technological challenges related to the on demand switching between power and H 2 production. This report provides a high-level technical assessment of a novel SOFC based H 2 production concept that averts the potential drawbacks of the SOEC systems. The novel concept combines the advantages of steam-reforming of natural gas to produce H 2 with the high efficiency power generation capabilities of a SOFC in a single package.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2020

Learning from existing photovoltaic technologies to identify alternative perovskite module designs

Perovskite solar cells have now become the most efficient of all multicrystalline thin film photovoltaic technologies, reaching 25.2% in 2019. This outstanding figure of merit has only been achieved on small lab-scale devices, with significantly lower performance when processed on larger more industrially relevant substrate sizes. Perovskite modules, connecting several smaller area cells together, are commonly demonstrated with a superstrate monolithic interconnection method. However, several other module designs exist and remain largely unexplored by the perovskite community. In this work, we review and highlight those alternatives and discuss their advantages and limitations. We propose that a singulated substrate-oriented module design, using metallic substrates, could provide a quicker path to seeing highly efficient, lightweight, and flexible perovskite modules on the market, while mitigating near-term technical risks. Finally, as an experimental starting-point towards this design, we demonstrate a substrate-oriented all-perovskite 2-terminal tandem with 18% efficiency.

14 SOLAR ENERGY↗

DOE OSTI2023

AutoTG: Reinforcement Learning-Based Symbolic Optimization for AI-Assisted Power Converter Design

Power converters are pervasive in modern electronic component design. They can be found in all electronic devices from household appliances and cellphone chargers to vehicles. Currently, designing new circuit topologies is hard because it requires human expertise based on experience and is difficult to automate. However, artificial-intelligence-assisted design can significantly facilitate the development of new power converters and/or improve the final result. Intelligently designed highly efficient power converters can have a significant effect on many important attributes, such as power efficiency, layout size, cost, heat dissemination, energy requirements, etc. We propose Autonomous Topology Generator (AutoTG), a reinforcement-learning-based framework that generates power converter topology candidates based on user specifications, optimized for user preferences. By modeling power converter design as a symbolic optimization problem, we sequentially sample components in an autoregressive manner until new topologies are formed, providing both the topology specification and the sizing (magnitude of each component parameter) of the proposed power converter. Here, we provide an empirical evaluation and show that AutoTG is able to generate varied high-efficiency topologies within component restrictions based on user input and show that previously unknown topologies can be found for further evaluation.

(AI)-based design↗

DOE OSTI2025

Total Recycling of Copper Cable Scrap and Production of Carbon Using Fast Microwave Technology

The recycling of cable scrap, particularly from discarded electrical wiring, is gaining significant attention due to the rising demand for copper and the need for sustainable management of electronic waste. Traditionally, mechanical and thermal processings have been used to recover copper and plastic from cables. However, these approaches are often energy-intensive, time-consuming, and costly in terms of equipment and labor. In this study, we present a simple and effective method for recovering materials from cable scrap using a domestic microwave oven. Cable pieces (2–2.5 cm long) were exposed to 700 W of microwave irradiation under rotation for 30 s, enabling the rapid and efficient separation of high-quality copper metal from the core wire, and activated carbon from the carbonized plastic sheath. Microwaves facilitate this process through Ohmic heating, which induces electrical resistance in the metal, generating heat that mechanically loosens the metal and carbonized plastic components. The process demonstrates high efficiency, achieving an 80% reduction in energy consumption compared to conventional processings. This fast and energy-efficient method shows strong potential for scaling up to industrial recycling, offering a cost-effective and environmentally friendly way to recover high-quality materials for further use or repurposing.

Bourlinos, Athanasios B. (ORCID:0000000256165993)↗

DOE OSTI2023

Enabling residential heating decarbonization through hydronic low-temperature thermal distribution using forced-air assistive devices

Space heating represents approximately one-tenth of the United States’ energy use and has a breadth of potential for emission reduction. An element of space heating, hydronic heat distribution methods, use water supply temperatures up to 82.2 °C (180 °F). However, this operating temperature can be incompatible with high-efficiency heat generation systems, which typically provide heating temperatures of up to 60 °C (140 °F). In this work, a low-cost retrofit solution is developed using experimentally validated computational tools by incorporating an airflow distributor that preferentially directs the airflow from a fan to enhance heat transfer over the finned-tube heat exchanger found in conventional baseboards. The same heat output of traditional baseboard heat distribution systems operating at higher water supply temperatures (71.1 – 82.2 °C) can also be achieved at lower temperatures (≤60 °C). Specifically, results indicate that the technology can produce more than a 46.7% improvement in the heat transfer output at temperatures as low as 60 °C (140 °F), effectively matching the same output range achieved by 71.1 – 82.2 °C (160–180 °F) water supply temperatures. An important benefit of this solution is that it utilizes the existing infrastructure as opposed to requiring the replacement of the entire distribution system. Additionally, this technology enables existing building infrastructure to be coupled with newer, high-efficiency heating systems such as condensing boilers, solar-thermal systems, and geothermal/air-to-water heat pumps that may produce lower water supply temperatures (60 °C). A geospatially resolved techno-economic and environmental analysis is completed and presented to further understand the equivalent carbon footprint of enabling higher efficiency heat generation systems with the improved efficiency heat distribution system disclosed. Using 2021 grid-average emission factors, an emission reduction of up to a 67.5% decrease (2658 kgCO 2 /yr) for a single-family home, depending on state and climate region, could be realized by replacing a traditional natural gas-fired boiler with an air-to-water heat pump coupled to the same high-temperature heat distribution system along with the low-cost retrofit solution. A complete CO 2 emission reduction of 6688 kgCO 2 /yr, depending on state and climate region, could be realized if all electricity is further renewably sourced. Thus, this study provides a possible pathway towards enabling the reduction of operational emissions in space heating.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2026

Prototype Development, Testing, and Modeling for a Solar Light-Trapping Planar-Cavity Particle Receiver (LTPCR)

Many applications for concentrating solar thermal power (CSP) technologies of high efficiency power cycles or thermochemical processes require higher operating temperatures and alternative heat transfer media. Inert solid particles for next-generation CSP and reactive gas and/or solid media for solar thermochemical processes are common options; however, these have significantly lower heat transfer capabilities than thermal oil, molten salt, or molten metal media. Conventional solar receivers operating temperatures >700 degrees Celsius face challenges including thermal performance and thermal-mechanical issues. To overcome these limitations, we have developed a novel light-trapping, planar-cavity receiver (LTPCR) that can heat solid-phase media within an enclosed receiver while maintaining a high aperture solar flux concentration for high efficiency. This paper presents progress on design, fabrication, and testing of a 100 kWt prototype receiver to demonstrate the LTPCR operability and its commercial feasibility.

14 SOLAR ENERGY↗