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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 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Formation of solitary zonal structures via the modulational instability of drift waves

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Solitons↗
DOE OSTI2023

Seismic Response Processing Module

The seismic response processing module is a Java based library that provides support for removing instrument response signals from seismic recordings. The response module provides support for EvalResp, PZF, PAZ, FAP, PAZFIR, PAZFAP, FIRFAP, and CSS response types and parallel processing support for transfer operations. Additionally, the response module uses the JSR-363 units of measurement specification to allow for transfer to and from a wide range of units types to represent the time-series.

Dodge, Douglas↗
DOE OSTI2020

Real-time dynamic wavelength tuning and intensity modulation of metal-clad nanolasers

To realize ubiquitously used photonic integrated circuits, on-chip nanoscale sources are essential components. Subwavelength nanolasers, especially those based on a metal-clad design, already possess many desirable attributes for an on-chip source such as low thresholds, room-temperature operation and ultra-small footprints accompanied by electromagnetic isolation at pitch sizes down to ∼50 nm. Another valuable characteristic for a source would be control over its emission wavelength and intensity in real-time. Most efforts on tuning/modulation thus far report static changes based on irreversible techniques not suited for high-speed operation. In this study, we demonstrate in-situ dynamical tuning of the emission wavelength of a metallo-dielectric nanolaser at room temperature by applying an external DC electric field. Using an AC electric field, we show that it is also possible to modulate the output intensity of the nanolaser at high speeds. The nanolaser’s emission wavelength in the telecom band can be altered by as much as 8.35 nm with a tuning sensitivity of ∼1.01 nm/V. Additionally, the output intensity can be attenuated by up to 89%, a contrast sufficient for digital data communication purposes. Finally, we achieve an intensity modulation speed up to 400 MHz, limited only by the photodetector bandwidth used in this study, which underlines the capability of high-speed operation via this method. This is the first demonstration of a telecom band nanolaser source with dynamic spectral tuning and intensity modulation based on an external E-field to the best of our knowledge.

Deka, Suruj S. (ORCID:0000000297812317)↗
DOE OSTI2024

Roles of temperature, materials, and domain inversion in high-performance, low-bias-drift thin film lithium niobate blue light modulators

We demonstrate a thin film lithium niobate electro-optic modulator operating at 456 nm with an RF voltage-length product of 0.38 V-cm and a bandwidth of 6.9 GHz. We test the dielectric relaxation of the modulator with sweeps of temperature and optical input power, and compare equivalent modulators with electrode materials of Cr-Au, Ti-Au and Al in terms of bias stability and current-voltage characteristics. We demonstrate bias stability over at least 8 hours with Al devices, and show relationships between drift, I-V characteristics and ferroelectric domain switching.

Celik, Oguz Tolga (ORCID:0000000264542306)↗
DOE OSTI2024

Fundamental bandwidth limits and shaping of frequency-modulated combs

Frequency-modulated (FM) combs based on active cavities like quantum cascade lasers have recently emerged as promising light sources in many spectral regions. Unlike passive modelocking, which generates amplitude modulation using the field’s amplitude, FM comb formation relies on the generation of phase modulation from the field’s phase. They can therefore be regarded as a phase-domain version of passive modelocking. However, while the ultimate scaling laws of passive modelocking have long been known—Haus showed in 1975 that pulses modelocked by a fast saturable absorber have a bandwidth proportional to effective gain bandwidth—the limits of FM combs have been much less clear. Here, we show that FM combs based on fast gain media are governed by the same fundamental limits, producing combs whose bandwidths are linear in the effective gain bandwidth. Not only do we show theoretically that the diffusive effect of gain curvature limits comb bandwidth, but we also show experimentally how this limit can be increased. By adding carefully designed resonant-loss structures that are evanescently coupled to the cavity of a terahertz laser, we reduce the curvature and increase the effective gain bandwidth of the laser, demonstrating bandwidth enhancement. Our results can better enable the creation of active chip-scale combs and be applied to a wide array of cavity geometries.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

The TPR domain of PgaA is a multifunctional scaffold that binds PNAG and modulates PgaB-dependent polymer processing

The synthesis of exopolysaccharides as biofilm matrix components by pathogens is a crucial factor for chronic infections and antibiotic resistance. Many periplasmic proteins involved in polymer processing and secretion in Gram-negative synthase dependent exopolysaccharide biosynthetic systems have been individually characterized. The operons responsible for the production of PNAG, alginate, cellulose and the Pel polysaccharide each contain a gene that encodes an outer membrane associated tetratricopeptide repeat (TPR) domain containing protein. While the TPR domain has been shown to bind other periplasmic proteins, the functional consequences of these interactions for the polymer remain poorly understood. Herein, we show that the C-terminal TPR region of PgaA interacts with the de-N-acetylase domain of PgaB, and increases its deacetylase activity. Additionally, we found that when the two proteins form a complex, the glycoside hydrolase activity of PgaB is also increased. To better understand structure-function relationships we determined the crystal structure of a stable TPR module, which has a conserved groove formed by three repeat motifs. Tryptophan quenching, mass spectrometry analysis and molecular dynamics simulation studies suggest that the crystallized TPR module can bind PNAG/dPNAG via its electronegative groove on the concave surface, and potentially guide the polymer through the periplasm towards the porin for export. Our results suggest a scaffolding role for the TPR domain that combines PNAG/dPNAG translocation with the modulation of its chemical structure by PgaB.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Innovative manufacturing technologies for low-cost, high efficiency PERC-based PV modules

The goal this project was to accelerate the deployment of innovative solar cell and module technologies that reduce the cost of PERC-based modules to best-in-class. New module integration technology was to be used to reduce the cost and reliance on conventional silver bus bar pastes and enhance cell efficiency. On the cell manufacturing front, the cost of PERC solar cells was to be reduced by introducing advanced metallization approaches to increase cell efficiency. These advancements will be combined with process optimization to target cell efficiencies in the range of 21 to 21.5%. This project will also explore the viability of a bifacial PERC solar cell design to enable cost savings through the use of thin silicon wafers. This project was terminated on 4/30/17 after four months of activity due financial challenges facing the recipient.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules

Cogenra’s Dense Cell Interconnect system was designed to use traditional front-contact cells and string them together into high efficiency and high reliability “supercells”. This novel stringer allows one to take advantage of the ~100 GW/year of existing cell production capacity and create a solar product for the customer that will produce more power and last longer than traditional PV products. The goal for this program was for Cogenra Solar to design and develop a first-of-kind automated solar manufacturing line that produces strings of overlapping cells or “supercells” based on Cogenra’s Dense Cell Interconnect (DCI) technology for their Low Concentration Photovoltaic (LCPV) systems. This will enable the commercialization of DCI technology to improve the efficiency, reliability and economics for their Low Concentration Photovoltaic systems. In this program, Cogenra Solar very successfully designed, developed, built, installed, and started up the ground-breaking manufacturing tools required to assemble supercells. Cogenra then successfully demonstrated operation of the integrated line at high yield and throughput far exceeding expectations. The development of a supercell production line represents a critical step toward a high volume and low cost Low Concentration Photovoltaic Module with Dense Cell Interconnect technology and has enabled the evaluation of the technology for reliability and yield. Unfortunately, performance and cost headwinds on Low Concentration Photovoltaics systems including lack of diffuse capture (10-15% hit) and more expensive tracker requirements resulted in a move away from LCPV technology. Fortunately, the versatility of Dense Cell Interconnect technology allows for application to flat plate module technology as well and Cogenra has worked with the DOE to utilize the learning from this grant to commercialize DCI technology for the solar market through the on-going grant: Catalyzing PV Manufacturing in the US With Cogenra Solar’s Next-Generation Dense Cell Interconnect PV Module Manufacturing Technology. This program is now very successfully building off of this work and commercializing the technology to enable increased solar adoption.

14 SOLAR ENERGY↗
DOE OSTI2018

High-Efficiency Solid State Heat Pump Module

The baseline heat pumping technology today is dominated by vapor compression refrigeration cycle that involves use of global warming potential fluids (e.g. hydrofluorocarbons HFC). Current regulations (e.g. 2016 Kigali agreement) and market needs are driving HVAC&R related building, automotive and aerospace industries to safe, compact and cost-effective systems with low global warming potential (GWP) footprint (i.e. direct GWP impact) and higher efficiencies (i.e. indirect GWP impact) and low life cycle cost. Among the solid-state technology options, electrocaloric heat pumping (ECHP) technology has potential to be more efficient, quiet and compact than vapor compression systems. However, electrocaloric technology is still at low maturity, as expressed by standard technology readiness level (TRL) assessments and hence was the focus of the current effort. During the current research effort, UTRC proved feasibility (TRL2/3) of the direct-air ECHP concept by demonstrating cooling of ambient air by 8.4°C (under no load conditions) in a laboratory environment. To the team’s knowledge this is the largest direct air cooling demonstration using electrocaloric technology. The technology was matured from lab-scale dime-sized materials to module-scale dimensions and further demonstrated the feasibility of integrating these electrocaloric materials into modules for providing direct-air cooling. The use of inexpensive polymer-based materials validates the economic feasibility of the proposed technology. Future effort is required to further mature this promising technology to TRL 4/5 demonstrating module and system performance at full capacity and efficiency. Maturity to beyond TRL4/5 could be done with limited potential field trials. Successful field trials can pave the way for commercialization. At full commercialization, electrocaloric based heating and cooling technologies have the potential to enable annual energy savings upwards of a quadrillion BTUs and reduction of 10s of million metric tons/yr of Green-House Gas (GHG) emissions in the US, leapfrogging emerging technologies and disrupting traditional cooling and heating systems in residential and commercial HVAC applications and enabling new applications. This would result in reduction of energy imports, greenhouse gas (GHG) emissions and help create US jobs in this new technical area.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Advanced QPSK Optical Modulators Using Lithium Niobate Thin Films (Final Scientific Report)

Lithium niobate thin film based optical modulator devices have been produced using this SBIR award. A bonding apparatus was developed that was used to bond lithium niobate to silicon at room temperature. The bonding apparatus was designed, assembled and qualified for production of thin film substrates. The optical properties of ion sliced thin films produced using this bonding apparatus was optimized to achieve low loss optical waveguides. Optical grating coupler and other component of the proposed optical modulator were designed. Preliminary results show the proposed method for making optical modulator meets the required customer specifications. All the required process steps for manufacturing of the devices were developed and optimized. Further funding is required to make a final prototype device that can be provided to customers.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Module OT PNM Field Demonstration Test Procedure

This document will detail a field demonstration test procedure for the Module OT device developed for the joint NREL-SNL DOE CEDS project titled "Modular Security Apparatus for Managing Distributed Cryptography for Command & Control Messages on Operational Technology (OT) Networks." The aim of this document is to create the testing and evaluation procedure for field demonstration of the device; this includes primarily functional testing and implementation testing at Public Service Company of New Mexico's (PNM's) Prosperity solar site environment. Specifically, the Module OT devices will be integrated into the Prosperity solar site system; traffic will be encrypted between several points of interest at the site (e.g., inverter micrologger and switch). The tests described in this document will be performed to assess the impact and effectiveness of the encryption capabilities provided by the Module OT device.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Improved Performance of Cu(InGa)(SeS) 2 PV Modules Using the Reaction of Metal Precursors. Final Report

This project “Improved Performance of Cu(InGa)(SeS) 2 PV Modules using the Reaction of Metal Precursors” was a partnership led by the Institute of Energy Conversion (IEC) at the University of Delaware with Columbia University and the Molecular Foundry at the Lawrence Berkeley National Laboratory. The aim was to develop pathways to improve Cu(InGa)(SeS) 2 (CIGSS) thin film photovoltaic modules using processes compatible with low manufacturing cost. The CIGSS approach investigated was a two-step process including deposition of metal precursor films following by reaction in hydride gases utilizing IEC’s novel reactor. The process was similar to that under commercial development by the project’s industry partner Stion. When Stion went out of business mid-project the focus changed to a rapid thermal process considered more commercially viable. Approaches to improve the performance of solar cells using the reacted films focused on two material innovations. First, the overall Ga content was increased to increase the operating voltage, which is desirable for scale-up to commercial modules. Second, the processing and performance advantages arising from Ag alloying were investigated. Advanced characterization guided process and material development including control of relative composition gradients. Research on the formation of Cu-Ga-In metal precursors utilized sputtering deposition which is normally used in commercial applications. The work resulted in processes for deposition of precursor stacks with increased relative Ga content and effects of deposition parameters on morphology and phase composition were established. It was shown that the metal precursor films have comparable phase composition and morphology so subsequent reaction follows from the same starting point. The addition of Ag to the metal precursors gave more uniform morphology and improved adhesion of reacted films which enable higher reaction temperature for faster processing. A novel outcome was the discovery of a previously undocumented material phase in sputter-deposited and evaporated Ag-Cu-In-Ga thin films. Hydride gas reaction processes including time-temperature-concentration profiles were developed for different precursor compositions. This enables control of composition profiles to engineer through-film gradients for solar cell optimization with characterization and simulations used to correlate measured film composition profiles to measurements of devices. In particular, the gradient of sulfur at the front of the CIGSS film was found to be critical. The simulations guided process development leading to improved reproducibility of devices improved performance with higher Ga content and higher voltage. With Ag-alloyed precursors, the reaction pathways leading were determined. A significant finding was that Ag-alloying increases the reaction rate to completely convert precursor films to the final chalcopyrite which could enable reduced reaction time to benefit manufacturability. To maintain potential commercial viability, the process under investigation was refocused to a rapid thermal process that could potentially be incorporated into an in-line process for manufacturing. Precursors with different composition were capped with an extra selenium layer and reacted in hydrogen sulfide 5-15 minutes, compared to typically 2 hours in the previous multi-step batch process. Critical RTP parameters were identified to control the reaction. Further optimization would be needed for high efficiency solar cells but pathways to high quality devices with further optimization and improved heating uniformity were developed. The project also developed new optoelectronic characterization approaches with a focus on development and application of spatial- and time-resolved photoluminescence and a custom mapping photoluminescence microscope built. It was shown how critical electronic transport properties strongly depend on the chemical composition of the material and that a wide range of samples show inhomogeneity on a length scale larger than the grains in the films. Additionally, two-photon excitation capability was developed to distinguish bulk vs surface losses. The project advances the state-of-the -art for precursor reaction processes in several ways that could impact manufacturing. This includes validation of approaches to increase voltage and establishment of model-guided control to form optimal composition profiles. The application of process control approaches with knowledge of phase formation and reaction pathways can be critically valuable in designing a large-scale process.

14 SOLAR ENERGY↗
DOE OSTI2021

Generalizable Mechanistic Understanding of Module-Level Light-Moisture and Thermal-Induced Instabilities in CIGS Photovoltaics (Final Report)

The objectives of this project are to identify the root causes of light, heat and humdity induced instabilities in the operation and accelerated testing of commercial Cu(In,Ga)Se 2 [CIGS] photovoltaic modules produced by major module manufacturers (e.g.: Solibro and MiaSolé), correlate them with module degradation/failure modes, and produce accurate service lifetime prediction models.

14 SOLAR ENERGY↗
DOE OSTI2021

Reliability and Power Degradation Rates of PERC Modules Using Differentiated Packaging Strategies and Characterization Tools

The reliability, durability and lifetime performance of passivated emitter, rear cell (PERC) modules used in real-world PV power plants is a critical challenge underlying the rapid adoption and bankability of these PERC cells, whose high efficiency help reduce the levelized cost of electricity (LCOE). We propose a degradation-science study of PERC module degradation pathways, benchmarking them relative to known degradation mechanisms and pathways of the incumbent aluminum back surface field (Al-BSF) modules exposed to real-world and accelerated exposure conditions.

14 SOLAR ENERGY↗
DOE OSTI2021

PV Module Design for Recycling Guidelines

The global growth of clean energy technology deployment will be inexorably followed by a parallel growth of end-of-life (EOL) products that bring both challenges and opportunities. Cumulatively, by 2050, estimates project 78 million tonnes of raw materials embodied in the mass of EOL photovoltaic (PV) modules. Owing partly to concern that the projected growth of clean energy technologies could become constrained by availability of raw materials, despite ongoing dematerialization efforts, significant attention under the umbrella of circular economy has been brought to recycling these technologies at EOL. Yet PV has not been designed with recycling at EOL in mind, and it presents challenges to returning embodied raw materials back to use in new products through recycling. This study aims to inform future designs to improve recyclability through synthesis of prior published works augmented by novel recommendations that result in a set of general design for recycling (DfR) guidelines, with a subset specific to PV modules. We further discuss how established trends in design of PV modules could affect recyclability. If adopted today, application of these DfR guidelines could help to mitigate tomorrow's resource scarcity, lower the barriers and cost for PV recycling, and enable a circular economy during the energy transition.

14 SOLAR ENERGY↗
DOE OSTI2023

Advanced Module Architecture for Reduced Costs, High Durability and Significantly Improved Manufacturability (Final Report)

This project demonstrated a new module architecture (referred to herein as Glass/Glass) using silicone edge seals and an interlayer polymer that reduces manufacturing costs, significantly streamlines manufacturing processes, and reduces cap-ex costs while improving module reliability. A prototype manufacturing process to fabricate this new module architecture was demonstrated with a significantly improved process cycle time for the lamination step from the current industry standard of 13.5 minutes to approximately 30 seconds for each of the individual edge seal and internal polymer application steps. Samples are fabricated, strenuously stressed, and characterized to quantify the cost benefits, hardware capacities and accelerated stress performance of the new architecture. These results are being compared to a standard, laminated baseline architecture using a Glass/EVA/Glass or Glass/Thermoplastic/Glass design that traditionally has high moisture vapor transmission rates (MVTR).

14 SOLAR ENERGY↗
DOE OSTI2022

PACT Module Design Acceptance Criteria (Research)

For the PACT center to both develop testing protocols and provide service to the metal halide perovskite (MHP) PV community, PACT will seek modules (mini and full-sized) for testing purposes. To ensure both safety and high-quality samples PACT publishes acceptance criteria to define the minimum characteristics of modules the center will accept for testing. These criteria help to ensure we are accepting technologies that are compatible with our technical facilities and testing equipment and can transition to large scale commercial manufacturing. This module design acceptance criteria document is for research partners (academia, national laboratories) and is different from the acceptance criteria for industry partners.

36 MATERIALS SCIENCE↗